Brave Fontier Water Vortex Arena Squad Building Guide

Brave Fontier Water Vortex Arena Squad Building Guide by Xerte

General Squad Building

When building a squad for the arena, if you want to optimize it you need to consider these major factors:

  • ATK – if your units have around 2k base ATK, they should be able to two-shot kill any enemy except Tridon if you sphere/LS for ATK boosts. Obviously, more is better.
  • HP – if your units can reach around 10k HP they’re safe from most one-shot kills short of enemy BBs. More is better.
  • AI – AI determines the optimal placement for your units. Some AI types are notoriously unreliable and should be avoided – you’ll want the majority of your units to be type 2 or type 3.
  • Drop Checks – determine how much BC your squad produces and thus how much support you’ll need from spheres/LS.
  • BB Type – anything that isn’t an AoE should be avoided if it’s not in the leader slot.
  • BB Effects – if a BB will help fill other units or buff damage, it’s noteworthy. It generally isn’t absolutely necessary, however.
  • LS – obviously your squad will need one. The most important leader skills are BC-boosting leader skills and ATK-boosting leader skills, though there are some marginally viable defensive leader skills as well.
  • ES – frankly speaking, most of the ES available to water units are pretty good. There are a couple bad ones, but an ES is never a drawback.

Unit Placement

Units attack in order, from top to bottom, so if you’re trying to optimise their AI, you’ll need to place them accordingly – some units BB more often if they’re near the top of the squad, some near the bottom, and others just don’t care. Units are arranged in this order, according to their squad management positions:

  1. Top Left
  2. Top Right
  3. Center
  4. Bottom Right
  5. Bottom Left

It should be noted that your units will actually be arranged differently when attacked by another squad. I haven’t really bothered looking into the position rules for that – losing doesn’t matter to your score, and unless you’re actually going for the ranking rewards, it’s preferable to lose your defensive matches (it helps everybody around you get a higher ABP, so they’re worth more points when you challenge them)


There are 3 major types of leader as far as the arena is concerned – damage, BB spam and survival. Many leaders are hybrids of two of these.

  • Damage leaders are typically used to try and maximise turn 1 kills. Ths makes the enemy counter-attack less dangerous; additionally, enemies drop BC at a higher rate if they’re hit when they’re already dead, so it does help fill BB gauges as well.
    • Typical leaders: Selena, Eliza, Mega, Dean
    • Tridon’s crit chance kinda helps on this line
    • Selena’s obviously the best of this type of leader if damage is your goal. Water hasn’t received many damage-boosting 7* leads that aren’t spark damage (which doesn’t help in arena)
  • BB spam leaders focus on getting all BB filled as much as possible – preferably all the way to SBB, which deals more than enough damage to compensate for lack of an ATK boost in the LS slot. BB spam leaders without an ATK boost will typically struggle to score many kills on turn 1 however, so they face a stronger counter-attack.
    • Typical leaders: Medina, Felneus, Phee, Tazer
    • Medina’s the best for this LS type. Tazer’s ok as well but stacks worse with spheres. Felneus and Phee are weak units at this point and should probably be avoided.
  • Survival leaders simply try to make sure the enemy attacks kill as few units as possible. You’ll generally need to have a very high BC gen squad to go with them, as with the exception of Selena these leaders don’t help much on the damage or BC gen fronts.
    • Typical leaders: Tridon, Zeldeus, Selena, Colt, Eve, Kuhla, Abel, Zerafalgar
    • Tridon’s a clear best choice for survival squads.
    • Selena pops up again, and she’s a strong choice for this as well – I’d argue in favour of her being water’s best leader at this point.
    • Zerafalgar provides less survivability than any other unit listed, and little other benefits. If you have Selena, you may as well use her over him. Or just about any survival lead except Tridon… few provide a strong enough advantage over Selena to be worth it.
  • Some players might want to use gimmick leads like Vernil, Belfura or Fei to mess with attacking players, but generally they’re not the best option. They’re still an option, I guess.


Spheres typically fall into the same types as leaders – there are damage boosters, BC boosters and survivability boosters. Typically your squad will want spheres that contrast the leader, as that’s what the squad would lack.

  • Damage spheres are typically used as the slot 1 sphere for any squad using a survival lead, as you often don’t need much more after a 30% HP increase if your units are imped.
    • Typical damage spheres: Amanohabaken-type spheres, Blighted Seal, Sky Harbinger, Hit Count spheres (Lexida, Shiny Anklet, Hallowed Skull,
    • Hit Count spheres provide a dual role as they’re also some of the best BC boosters in the game for arena. They don’t boost BB damage, so be careful using them without an ATK lead as it may take more than one BB or an SBB to one-shot opponents.
  • BC spheres are typically used as the slot 2 sphere for any squad that isn’t using a BB spam lead, and often still used in those squads to make sure the squad hits SBB regularly.
    • Typical BC spheres: BC Drop Rate spheres (Virtue Stone, Sol Creator, Celgrad, Xentar, Ishrion, Phantom Gizmo…), Hit Count spheres, BB Fill rate boosters (Alzeon Pearl, Urias, etc.), BB regen spheres (Queen’s Tear, Fake Stone, Evil Shard, Dandelga, etc.)
  • Survival spheres are typically used if your leader doesn’t provide any HP. As there are so many of these, you’ll want to tend towards ones that also provide a decent amount of damage or BC support as well.
    • Typical survival spheres: Xentar, Ishrion, Phantom Gizmo, Dandelga, Lexida, Sky Harbinger… pretty much anything that provides at least 30% HP, really.
  • Other spheres that might be used include gimmicky status infliction spheres (paralysing/cursing a unit is almost effectively killing it), status immunity spheres (to deal with those) and crit spheres (to maximise damage as much as possible)

Unit Guide

Pros and Cons

I’ve defined Pros and Cons with the following rules:

ATK: ATK considered a pro if 2000+ as Lord. ATK considered a con if the unit cannot reach base 2000 ATK with breaker type without imps. ATK not considered on non-AoE units.

HP: HP considered a pro if 6000+ as Lord. HP considered a con if the unit has below 5500 HP and Anima isn’t farmable.

Drop checks: Considered a pro if the unit is above 25 drop checks. Considered a con if the unit is below 20 drop checks.

AI: Type 1 and Type 3 AI are considered a pro. Type 4 and Type 6 AI are considered a con.

BB: Considered a pro if it has a relevant buff. Considered a major con if it doesn’t AoE. Considered a minor con if it has a low BB mod.

ES: ES considered a pro if it’s relevant. Not having an ES is not considered a con.

LS: LS considered a pro if it’s strong within its subgroup. No LS is considered a con as you can choose not to use it but it’s noted when they’re not worth using.

AI Types

I’m referring to the types as numbered in this guide.

I’m also suggesting placement rules, as follows:

Early: Unit is most effective when placed as early as possible. If multiple units in your squad need to go early, prioritise the one that will deal the most damage.

Middle: Unit is most effective in the middle of the squad. Only applies in certain situations – type 4 AI units in squads that deal a lot of damage with regular attacks will want to go around the middle so their BB has a chance to activate before enemy units die.

Late: Unit is most effective when placed as late as possible. Higher damage units may still want to go first out of this group.

Anywhere: Place the unit anywhere in the squad after arranging the other units. If it has a relevant buff, you may want to place it sooner rather than later.

Units will follow the following format:


[Explanation of the unit’s strengths and weaknesses]

  • Pros: List of pros
    Cons: List of cons
    AI Type: AI number
    Placement: Suggested placement locations
    Notes: Any unit-specific advice

The units have been placed into tiers, but I haven’t yet gone to the effort of sorting them within said tiers. In addition when the thread is first posted there may be formatting errors as I typed up the guide in notepad++ and may have made minor mistakes with the formatting. I’ll read through everything and fix it after posting.

Top Tier


At the moment, Selena is easily water’s best arena unit, meeting the minimum recommended stats, great AI, LS and drop checks and having access to her extra skill which will protect her from being one-shotted on turn 1, or from potential BB counterattacks if you don’t use BB on turn 2. While you can only have her ES active on one Selena, it’s worth noting that she still competes with all other water arena units even without it. Dupes are fine.

  • Pros: 36 drop checks, Type 3 AI, >2000 ATK in all types, >6000 HP in all types, Angel Idol + 20% stats ES, 100% ATK/30% HP LS
    Cons: Only one Selena can have ES active
    AI Type: 3
    Placement: Anywhere
    Notes: Requires Lexida to be at full potential, but still a strong sub unit without it if you use a dupe Selena


The best new RS unit released for water since the advent of 7* units (ignoring any unts we don’t have yet), and the first one without a real drawback since Signas and Raydn. Medina also comes equipped with a nice BB fill on her BB, the strongest BB spam LS of all water units, a 4 BC fill per turn ES, 27 drop checks, 2300 ATK and 6500 HP. Selena’s advantages are only in her AI, ES and 36 base drop checks, so Medina might be better filler after the first Selena, depending on your squad.

  • Pros: 2300 ATK, 6500 HP, BB fill on BB, BB fill on ES, 27 drop checks, strongest BB spam LS in water
    Cons: None
    AI Type: 2
    Placement: Early
    Notes: Her instant BC fill means she should go as soon as possible, even over other type 2 units


The first 7* RS unit. As a 7* unit, Tazer has above-average stats compared to most of what’s viable in water. His only major drawback is that his SBB is single target, so if it charges, it’s a problem. LS is spark-based on one side, somewhat effective BB spam on the other – usable. ES just adds 80% ATK when his BB gauge is full, but at that point his BB is already likely to kill most opponents, so it rarely matters.

  • Pros: 2400 ATK, 6700 HP
    Cons: SBB is detrimental if it charges
    AI Type: 2
    Placement: Early


Again with the drawbacks! This time it’s drop checks. Zerafalgar has a paltry 16 drop checks. Otherwise, he’s got high stats and an ES that lets him compensate for himself alone. His LS really isn’t worth using – out of all 6* and 7* units, only Dean has a survival-boosting LS which is weaker.

  • Pros: 2400 ATK, 6900 HP, ES helps ensure he fills BB
    Cons: 16 drop checks
    AI Type: 2
    Placement: Early
    Notes: Not a good option for hit count/BC drop spheres unless you really need the extra BC gen


Barring an early release of Iris, Vernil will be the most recent RS unit added for water. Statistically, he’s very strong, but doesn’t carry a lot of utility for arena purposes – his BB buffs only matter if the opponents survive it, and his ES and half of his LS are dedicated to spark damage (the other half of his LS is status infliction, which is unreliable but trolls other players when they attack you – not that defensive wins really matter in vortex arena; if anything, they’re slowing down the players around you and making it harder to reach the milestones). Still, he’s got a high damage output at 2625 Lord ATK and a high drop check total, making him a completely viable unit.

  • Pros: 2625 ATK, 6540 HP, 30 drop checks
    Cons: None
    AI Type: 2
    Placement: Early


The first 50% mitigator, and a wildcard in this arena. Zeldeus is a terrible arena unit at 6* – low drop checks (16), non-damaging BB, only 1653 ATK. However, in its 7* form, it’s suddenly considered one of the strongest arena units in the entire game, with an absolutely massive AoE BB with his ES active, 40 drop checks and huge HP. In either form he mitigates which can potentially prevent a one-shot wipe from enemy BB, but at 6* not really worth using just for that. Has a semi-viable defensive LS, but it doesn’t really match up to Selena, only offering a small amount of extra survivability in exchange for no offensive merit.

  • Pros: 2000 ATK, 6950 HP, 40 drop checks, stat boost ES, 510% BB modifier with ES sphere equipped, Mitigation BB with AoE damage
    Cons: None
    AI Type: 2
    Placement: Early
    Notes: Golem Core is not strictly necessary – Oulu gets more HP and more damage while at high HP with Sky Harbinger, for example


The ol’ OP SBS unit. Not quite as OP in arena, but still a very valid option with absolutely massive HP – you’ll rarely see him get one-shotted by anything short of an SBB in the arena. Tridon’s main drawback is an expensive BB (33 BC). However, his ES provides him a little extra BC to compensate and his shield adds a bit of survivability if he doesn’t kill, and his LS is the strongest survival-type LS available for the water arena – with a hidden crit factor, so it has a little offensive merit.

  • Pros: Ridiculous HP with ES active, 2280 ATK, Shield, strongest defensive LS in water
    Cons: BB is slightly more expensive than usual at 33 BC
    AI Type: 2
    Placement: Early
    Notes: Tridon’s Trident is pretty much necessary for him because of the sheer bulk he gets while equipping it. It’s actually necessary for his BC fill per turn portion of his LS, too.

Mid Tier


The very first mock unit, now at 6*. Karl’s a strong all-rounder unit with no real weakness, and his LS is great for ensuring turn 1 BB even for low drop check squads.

  • Pros: 2250 ATK, 6300 HP, Strong BB Fill LS
    Cons: None
    AI Type: 2
    Placement: Early


A fairly average all-rounder unit with no noticeable cons. High HP, BB has a chance to lock down enemies it doesn’t kill with paralysis, but LS isn’t noteworthy.

  • Pros: 6400 HP, chance to paralyze with BB
    Cons: None
    AI Type: 2
    Placement: Early


Another average unit. Rhein has a few pros – type 3 AI, 2100 ATK, DEF Ignore actually matters in arena (typically around +700-1000 damage), and his LS is a good damage boost if you don’t have Selena. He’s also farmable, so if you paid attention to types when farming him, you’ll easily have a strong Anima or Breaker.

  • Pros: Type 3 AI, 2100 ATK, 6000 HP, DEF Ignore matters, Usable LS, Farmable (Your choice of type)
    Cons: None
    AI Type: 3
    Placement: Anywhere
    Notes: As a damage buff, other units in your squad can benefit from DEF Ignore if Rhein moves before them.


The earliest 6* release that’s still particularly usable in the arena. Signas carries almost every good trait for an arena unit – she has type 3 AI, 2200 ATK, 6370 HP and an AoE BB. Her BB carries Injury, which potentially protects you units if she fails to kill. Her only low point is her average 21 drop checks, which is still acceptable. Her LS isn’t usable in a mono arena.

  • Pros: Type 3 AI, 2200 ATK, 6370 HP
    Cons: None
    AI Type: 3
    Placement: Anywhere


Raydn is pretty much a clone of Signas with lower stats – only 1900 ATK and 6000 HP, but otherwise practically identical. He doesn’t have the Injury debuff, however his LS usable and provides 65% ATK.

  • Pros: Type 3 AI, 6000 HP
    Cons: None
    AI Type: 3
    Placement: Anywhere


A unit with high drop checks, decent ATK and high HP. Eve’s only major problem is her AI is type 4. Eve’s LS is very similar to Kuhla’s, providing 30% HP and a slight healing factor – so Selena, Zeldeus and Tridon are preferable.

  • Pros: 6400 HP, 28 drop checks
    Cons: Type 4 AI
    AI Type: 4
    Placement: Middle (ATK LS), Late (Other LS)


The water vocaloid. Kaito has the always good type 3 AI, and decent stats all around, so he’s a fairly strong arena unit. The stats portion of his LS is impossible to activate in the arena (even in regular arena), however, leaving him with just 5% mitigation and a BC fill when attacked that has a chance to fail – not ideal, but you dont have to take him as leader.

  • Pros: 2000 ATK, 6150 HP, Type 3 AI
    Cons: None
    AI Type: 3
    Placement: Anywhere


Another 7* unit with high stats and a drawback; this time however it’s more serious – Colt has type 4 AI. Colt has a fairly strong leader skill which works best if you slot crit-boosts, combining 30% HP and 150% crit damage. However, you’d generally have to give up BC generation to get enough crit to make the most of it. His BB gives crit, which is a relevant damage boost in arena regardless of his LS. Colt’s ES give shim a very nice all-round stat boost when equipping his unique sphere.

  • Pros: 2500 ATK, 6700 HP, high HP with ES sphere active, crit boosting BB
    Cons: Type 4 AI
    AI Type: 4
    Placement: Middle (ATK LS), Late (Other LS)
    Notes: Ice Blade isn’t totally necessary as it provides very little over a Malice Jewel; other GGC-esque spheres with %HP may appeal instead.


Another average unit for arena. Practically identical to Arius in stats, but Kuhla’s BB carries an instant BC fill effect that pushes her above him as a unit. LS is ok for survivability, but if you have Selena, Zeldeus or Tridon they easily outclass Kuhla’s LS.

  • Pros: 2000 ATK, 6000 HP, BB Fill on BB
    Cons: 16 drop checks
    AI Type: 2
    Placement: Early
    Notes: Her instant BC fill means she should go as soon as possible, even over other type 2 units

Low Tier


The glorified evo mat for Fang, Fei isn’t a terrible arena unit (though definitely outclassed). His biggest drawbacks are his low-end ATK (1715) and drop checks (18), but if you can get past that, the rest of him isn’t terrible. His BB grants DEF Ignore, which effectively gives him an extra 700-1000 or so damage depending on the targets, which somewhat compensates his low ATK stat. He also has plenty of HP, and hopefully if you wanted to use him you farmed him as Anima. His LS has some gimmicky uses as a defensive lead, though it’s not quite on the same troll level as a status inflicting leader like Vernil.

  • Pros: 6035 HP, farmable as Anima, DEF Ignore BB
    Cons: 1715 ATK, 18 drop checks
    AI Type: 2
    Placement: Early
    Notes: As a damage buff, other units in your squad can benefit from DEF Ignore if Fei moves before them.


Another generally average unit with a single drawback. In this case it’s her AI – type 4, which relies on enemy HP being below a threshold. Belfura has an interesting LS for arena which can troll the opponent with curse or paralysis at any time, but the spark portion doesn’t matter much.

  • Pros: 6350 HP
    Cons: Type 4 AI
    AI Type: 4
    Placement: Middle (ATK LS), Late (Other LS)


A mostly average unit with subpar ATK. Has a strong LS for BB spam squads, but nothing else of note.

  • Pros: 6000 HP, BB spam LS
    Cons: 1700 ATK
    AI Type: 2
    Placement: Early


A single target BB user with otherwise acceptable stats. Noah’s SBB is a little too expensive to realistically be achieved without a BB spam lead and spheres. His LS isn’t impressive for arena as BB Cashback only takes effect after a BB is used.

  • Pros: 2080 ATK, 6090 HP
    Cons: Single target BB (expensive AoE SBB)
    AI Type: 2
    Placement: Early


An average unit with subpar drop checks, but otherwise usable stats. Usable LS for BC generation if your squad has low drop checks overall.

  • Pros: 2000 ATK, 6000 HP
    Cons: 16 drop checks
    AI Type: 2
    Placement: Early


Time hasn’t treated Mega well. He’s actually been buffed quite a bit just recently, however, leaving his HP as his only major drawback. His LS is subpar at present as well.

  • Pros: 2000 ATK, 28 drop checks
    Cons: 5200 HP
    AI Type: 2
    Placement: Early


The original BB spam lead. Felneus’ stats have been outclassed heavily due to powercreep, but his leader skill is still relevant and he has a decent AI.

  • Pros: Ares LS, Type 3 AI
    Cons: low BB mod (190%), 1600 ATK, 5400 HP
    AI Type: 3
    Placement: Anywhere


Another unit outclassed by the passage of time. Dean’s SBB is a particular concern – it only needs BC to fill after BB, but unlike his BB it’s not an attack; hence charging SBB is bad for him. He’s got a decent AI, but otherwise is a weak unit. Leader skill is kinda viable if you have no better choice for an ATK LS.

  • Pros: Type 1 AI
    Cons: Cheap non-attack SBB, 1740 ATK
    AI Type: 1
    Placement: Anywhere


The water Sibyl. Eliza’s a pretty average unit, bar her low stats – thankfully you can choose her type when she’s available. Unthankfully, she can’t reach par base stats in both ATK and HP simultaneously. She also has a slightly over-expensive BB at 30 BC. Her LS is usable in the arena, providing 65% ATK and a more or less useless spark bonus – which obviously doesn’t compete with Selena, but is one of the best ATK LS after Selena’s nonetheless.

  • Pros: Can choose her type when she’s available
    Cons: 1770 ATK, 30 BC cost BB
    AI Type: 2
    Placement: Early


A single-target BB user that has very high drop checks. Her SBB is AoE and she has type 3 AI, so if you can charge it consistently it’s usable. Stats are acceptable, but nothing stands out other than drop checks as noted.

  • Pros: 36 drop checks, Type 3 AI
    Cons: Single Target BB (AoE SBB is usable)
    AI Type: 3
    Placement: Anywhere


A single target BB user with what used to be considered a ridiculous ATK stat. SBB is AoE, but very high BC cost. LS isn’t noteworthy.

  • Pros: 2350 ATK, 6070 HP
    Cons: Single Target BB (expensive AoE SBB)
    AI Type: 2
    Placement: Early


One of the xmas RS batch. Jack has an extremely high BB modifier that manages to be lower than his SBB modifier (wut), very high HP and very low drop checks. His LS is an all-rounder, adding a low modifier to a lot of stats, but not really enough to any one thing to be significant.

  • Pros: 7000 HP, huge BB modifier
    Cons: 1800 ATK, 12 drop checks
    AI Type: 2
    Placement: Early


The water Battle Maiden. Serin retains her high drop checks and 116% damage distribution on normal attacks, but her stats as a 5* unit simply don’t compete anymore. We’ve been told she’ll get a 6*. Eventually. Probably not before the water arena. Serin has pretty much the weakest pure ATK LS for arena purposes, if you somehow don’t have someone better.

  • Pros: 26 drop checks, 16% bonus damage on normal attacks offsets low ATK somewhat
    Cons: 1500 ATK, 5400 HP
    AI Type: 2
    Placement: Early

Avoid Using


As a single-target BB user, Sergio isn’t really recommended. Still, he has bearable drop checks and good AI, and single target BB don’t need as much ATK so his lack there doesn’t matter too much.

  • Pros: Type 3 AI
    Cons: Single target BB
    AI Type: 3
    Placement: Anywhere


Sergio, but with lower stats in every category. Only has type 2 AI. SBB is AoE, if he can reach it.

  • Pros: None Cons: Single target BB
    AI Type: 2
    Placement: Early


Basically an even weaker Zephu with higher drop checks. Stya’s SBB has a higher cost than Zephu’s, making it even harder to get her to it.

*Pros: 26 drop checks Cons: Single target BB, only 5150 HP
AI Type: 2
Placement: Early


A single target BB user with high drop checks and low HP. LS is spark-based and not worth using.

  • Pros: Type 3 AI, 2000 ATK, 32 drop checks
    Cons: 5500 HP, single target BB
    AI Type: 3
    Placement: Anywhere
    Notes: Highly preferential for hit count spheres due to drop checks, not needing ATK for BB kills


Abel has a pure support BB which increases DEF and Crit, giving it a small amount of offensive merit, but not really worth using for that. She’s also subpar in pretty much every relevant stat, but her leader skill is worth 41% HP.

  • Pros: Semi-viable defensive LS
    Cons: No inherent damage on BB, 18 drop checks, subpar stats
    AI Type: 2
    Placement: Early (to maximise crit buff)


Usually, healers aren’t particularly recommended for arena. Elimo’s heal comes with mitigation, however, which means after using it you can usually survive at least one BB. As a pure healer, her AI only looks at your squad’s HP, so placement doesn’t matter. She has a high BB chance when meeting her conditions.

  • Pros: High BB activation chance, >6000 HP in all types, Mitigation buff + Heal can matter Cons: BB and SBB deal no damage
    AI Type: 5
    Placement: Anywhere


Another water healer. Tiara’s SBB attacks, but she neither has high BC gen nor good stats – her SBB damage output is on a similar level to a stronger unit’s BB. The ATK portion of her LS is impossible to activate ina mono squad, but the 2 BC fill per turn works, not that it’s worthwhile by itself.

  • Pros: Type 1 AI
    Cons: Non-attack BB, 1550 ATK, 5400 HP, 14 drop checks
    AI Type: 1
    Placement: Anywhere


Healer/mitigator on BB, attacker on SBB. Tesla has acceptable stats all around, and a usable LS (Selena still preferable), but her lack of damage on BB is a detrimental factor, as is her healer-type AI when her SBB charges. Still, healing and mitigating simultaneously is actually strong in arena, though simply killing the opponent is preferable.

  • Pros: 2100 ATK, 6150 HP, heal/mitigate BB
    Cons: AoE damage only on SBB, SBB only triggers on enemies < 25% HP, BB only triggers on allies < 25% HP AI Type: 6
    Placement: Middle (ATK LS), Late (Other LS)


A healer with an attacking SBB that would be great for arena if only for his BB not attacking. Rigness has a fairly pathetic LS when it comes to arena usage – it gives a very slight regen effect and status immunity.

  • Pros: 6185 HP, SBB is great if it charges
    Cons: AoE damage only on SBB
    AI Type: 2
    Placement: Early

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