Stone Ocean Infinity Boss Thursday rotation

F.F.

The weekly endgame raid from Stone Ocean. It scales across 5 difficulties, from Normal up to Hell, and acts 6 times per cycle at the hardest setting.

6 Attacks / cycle

10,000 Damage Reduction

20,000 Secondary Defense

5.0M Attack Power

Active tomorrow — rotation pinned to Thursday.

TL;DR — Thursday Infinity Boss

The only Infinity Boss with a real Attack stat — shields and flat Damage Reduction matter here. She splits into Plankton Colonies on Stance break, so the fight is multi-phase.

⚠ The danger

Single-target-only comps stall on the split phase. With nothing to clear the Plankton Colonies, she never reforms back into a damageable F.F.

How to beat F.F.

Two unique damage levers here: shields/flat DR (because she actually hits with real Attack, unlike every other boss) and AoE clear for the split phase. The fight runs on Sunny weather, NOT Dampness — to fire any Dampness-dependent kit (player F.F.'s Microplankton scaling, Lang Rangler's zero-G zone, Squalo's rain synergy), Anjuro Katagiri is the only Dampness applier on the roster. His humidifier converts the fight's terrain mid-battle.

Damage levers

Infinity Bosses have infinite HP — the only thing that matters is how much damage you can squeeze out. These are the levers that scale damage in this specific fight.

Shields + flat DR — Jonathan's team shield, Ermes B shield distribution, Tonio's heal aura matter more here because F.F.'s real Attack is a survival problem.
AoE clear — keeps up with 2 Colonies → 6 Tiny Colonies → reforms F.F.
Anjuro Katagiri — his humidifier applies Dampness mid-fight, enabling F.F./Lang/Squalo water synergies on top of the Sunny default.

Boss skills

4 skills. Every description below is the in-game skill text exactly as the game presents it — no paraphrasing, no fan summaries.

Active CD 15s

F.F. sprays part of its body to inflict “Micro Plankton” on all units.

Ultimate

When its Energy is maxed, F.F. generates several black liquid tentacles on the battlefield. The tentacles strike random enemies, dealing AoE damage equal to 700% of Attack to all units within 1 tile.

Passive

When F.F.'s Stance Bar depletes, it splits into 2 Plankton Colonies. When these Plankton Colonies take N% damage, they further split into 3 Tiny Plankton Colonies. When Tiny Plankton Colonies take N% damage, they will transform back into F.F. and become Weakened. Each time F.F. depletes its Stance Bar, its maximum Stance increases, and all Plankton Colonies will absorb more damage before splitting.

Passive

All Plankton Colonies share their skills: Plankton Colonies automatically attack enemies near them. Shatters upon taking a certain amount of damage, dealing damage equal to 300% of F.F.'s Attack to nearby enemies and inflicting “Micro Plankton” on them.

Stance Bar — the only burst window that matters

Infinity Bosses have infinite HP. Your score is your total damage output, not a kill. Every boss has a Stance Bar above its health bar. Empty it and the boss is stunned for 5-10 seconds and takes +100% damage from all sources — that window is the entire game. Crowd control (Stun, Freeze, Silence, Banish, Suppress) does NOT actually control the boss. Bruno's Zipper Space banish, Mariah's Magnetic Force Stun, Joseph's Hermit Purple bind — none of them lock the boss in place. They earn their slot because CC effects deal bonus Stance damage, which shortens the time to break.

Save every Ultimate for the Stance break — the +100% modifier doubles the burst.
CC kits are useful for Stance damage contribution, not for shutting the boss down.
Don't burn damage during invulnerability phases (Cool Ice flight, F.F. split, etc.) — Stance can't drop there either.

⚠ Don't bring

Single-target-only team — stalls completely on the split phase.
Skipping Anjuro and expecting Dampness synergies — the fight is Sunny by default; without Anjuro, no Dampness, no water-comp scaling.

Weather: Sunny

Sunny by default — bring Anjuro Katagiri to apply Dampness mid-fight.

Sunny

Increases all units' Attack by 5%.

No playable character on the roster has a passive bonus on Sunny. Treat the terrain as flavour.

Boss numbers explained

F.F.'s combat stats at Hell, the top difficulty. Each card says what the number does and whether it's unusual for an Infinity Boss — so you can see at a glance what makes this fight different.

Attack Power (Hell)

5,000,000

Unusual: almost every Infinity Boss ignores its Attack stat and deals damage purely through Crit. F.F. swings with a real Attack value on top, so flat damage reduction and shields help more here than against the others.

Attacks per cycle (Hell)

Typical Infinity Boss: 5 attacks — this one throws more, so sustain and healing matter more.

Damage Reduction

10,000

In line with a typical Infinity Boss — it shrugs off a flat chunk of every hit.

Secondary Defense

20,000

In line with a typical Infinity Boss — a second defense layer on top of normal Defense.

Crit Resistance (Hell)

40,968

How well the boss resists YOUR crits. To reach the +90% Crit Boost cap your attacker needs Crit ≈ 47,468, which no realistic build hits — so for Hell content lean Crit Damage % + Final Damage % over raw Crit Boost.

Crit Damage (Hell)

34,140

The boss's own Crit Damage multiplier — used when the boss crits you. Most Infinity Bosses don't deal real damage from their Attack stat, so this only really hurts on F.F. (the only boss in the rotation with a real Attack value).

How the difficulties scale

Climbing from Normal to Hell only grows two things: Crit Resistance (how hard it is for YOU to crit the boss) and Crit Damage (its own crit multiplier). Defense, attack pattern and speed never change. So a higher tier is the same fight where your crit chance suffers more — pick the highest row your team can survive.