Diamond is Unbreakable Infinity Boss Monday rotation

Akira Otoishi

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

5 Attacks / cycle

12,000 Damage Reduction

12,000 Secondary Defense

Active in 5 days — rotation pinned to Monday.

TL;DR — Monday Infinity Boss

Diamond is Unbreakable boss. His Ult teleports to the farthest target and deals 2400% ATK divided equally among everyone hit — a lone back-line carry eats the full 2400%.

⚠ The danger

Sending one isolated long-range character to the back line. Akira's Ult finds them, splits the 2400% among zero neighbours, and one-shots them.

How to beat Akira Otoishi

Damage maximization here is positional, not counter-based. Cluster your team so the 2400% Ult divides across multiple bodies, or run a full back-line so no one is the positional outlier. The fight runs in Thunderstorm — a handful of playable characters (Kenzou, N'doul, Squalo, Anjuro) pick up passive bonuses just by being in the fight. Pesci or Will refill what his energy-drain basic absorbs. The Chili Pepper Battery is a separate target on the field; destroying it during recharge cripples his Attack/Defense scaling.

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.

Thunderstorm weather synergies — Kenzou, N'doul, Squalo, Anjuro all pick up passive buffs that activate on this fight's terrain.
Energy battery kits (Will, Speedwagon, Pesci) — refill what his basic drains so your Ult cycle stays on rhythm.
Battery destruction during recharge — drops Akira's Attack/Defense scaling.

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 10s

Deals damage equal to 500% of Attack to the nearest enemy and absorbs 100% of the target's Energy.

Ultimate CD 20s

Teleports to the farthest target and strikes all nearby enemies, dealing total damage equal to 2400% of his attack, divided equally among all affected units.

Passive

Chili Pepper has 100%0, Chili Pepper teleports to the battery to recharge. While recharging, Chili Pepper cannot be Stunned.

Passive

When Chili Pepper's Stance Bar depletes, it becomes Stunned for 5 seconds, during which it takes 100% more damage. However, if Chili Pepper has enough Energy, it will consume 3000 Energy to negate the Stun effect. Crowd-control effects deal more stance damage to Chili Pepper's Stance Bar.

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

A single isolated ranged carry at the back (Hol Horse, Sale, lone-Squalo) — the Ult finds them and deletes them.
A tank-front + four-mixed-positions comp — the lone deepest character becomes the Ult target every cycle.

Weather: Thunderstorm

Thunderstorm — four playable characters (Kenzou, N'doul, Squalo, Anjuro) gain a passive weather buff.

Thunderstorm

Inflicts Dampness on all units. All units take 50% more damage from damage-over-time effects (except Burn). All units lose 1 stack of Burn every 2 seconds. Every 10 seconds, lightning bolts strike all units on the battlefield, dealing damage equal to 20% of their Max HP and Stunning them for 3 seconds.

Characters that benefit from this terrain

These playable heroes have a passive bonus that activates on Thunderstorm. Slotting one of them adds free utility the boss can't disable.

Boss numbers explained

Akira Otoishi'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.

Attacks per cycle (Hell)

In line with a typical Infinity Boss.

Damage Reduction

12,000

Cuts a flat amount off every hit you land. Typical Infinity Boss: 10,000.

Secondary Defense

12,000

A second defense layer stacked on top of normal Defense. Typical Infinity Boss: 20,000.

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.