ネクロバインダー

• Type: Power
• Cost: 2
• Effect: Revive 5. Whenever Osty loses HP, all enemies lose that much HP.

Upgraded

• Cost: 2
• Effect: Revive 8. Whenever Osty loses HP, all enemies lose that much HP.

A-tier

A unique Power that turns Osty's HP loss into AoE damage. The more HP Osty loses, the more damage goes out to all enemies, which flips the usual "Osty is fragile" problem into an offensive weapon — use Osty as a bait and chip the whole room.

Combos explosively with Bone Shard (sacrifice Osty to deal 9 AoE + 9 Block): every HP point lost when Osty dies gets mirrored onto every enemy. Reviving Osty up with massive Revives and then crashing Osty's HP turns it into a Board Wipe button. The 5-8 Revive on install also tops Osty up immediately.

Rating: A-tier — a creative Power that converts Osty HP management into an attack vector.

• Install Necromastery before playing Bone Shard — Osty's death deals huge AoE
• Keep Osty high HP (Revive 25 etc.) then crash it quickly to dump big AoE damage
• Does not directly stack with Unleash (which scales with current HP), but offers a parallel HP-to-damage strategy
• Revive 5-8 on install instantly puts Osty at safe HP

• Bone Shard: sacrifice Osty for 9 AoE + 9 Block. Necromastery mirrors the HP loss onto every enemy as more AoE
• Revive: Revive 20-25 heals Osty fully. Later HP decay turns into AoE damage via Necromastery
• Sacrifice: sacrifice Osty for Block equal to 2x its max HP. Stack with Necromastery for AoE + big Block combo
• Encouragement: Retain, Revive 3, Osty +5 HP. Adds HP buffer that Necromastery can later convert to damage

• Necrobinder Necromastery Combo (Key card) (A-tier)