The Reaper Lethal Build focuses on setting up instant-kill conditions and executing enemies in a single decisive moment. Rather than grinding enemies down with repeated damage, this build assembles specific conditions — Doom at the HP threshold, Reaper Form active, or a particular hand combination — then fires a kill card that bypasses normal HP. It is the highest-ceiling build for the Necrobinder but demands disciplined setup and reliable survival during the preparation phase.

• Reaper Form: The defining Power — transforms the Necrobinder, amplifying Doom triggers and enabling lethal effects that other forms cannot access.
• End of Days: Skill that triggers instant-kill or massive Doom burst when conditions are met; the primary finisher in Reaper Form.
• Countdown: Power that passively accumulates Doom each turn, advancing the kill condition without spending cards on it.
• Scourge: Active Doom applicator that pushes an enemy over the lethal threshold precisely when needed.
• Delay: Skill that postpones an enemy's action, giving an extra turn to reach the kill condition when on the edge.
• Defy: Skill that generates Block or disrupts enemy timing, covering the setup phase vulnerability window.
• Reap: Attack that restores HP on kill — used to recover after executing one enemy and immediately continuing into the next.

• Funerary Mask: Triggers on death events; enemies killed by Doom or Reaper effects activate this relic for run-wide bonuses.
• Undying Sigil: Keeps the player alive through the multi-turn setup, allowing Reaper Form to come online before taking lethal damage.
• Ivory Tile: Osty synergy — if Osty is part of the kill condition (e.g., Osty reaching 0 HP triggers a lethal effect), this relic helps manage the timing.

1. Obtain Reaper Form as the first priority — the entire build revolves around its active state, so securing it in Act 1 or early Act 2 is essential.
2. Stack passive Doom sources (Countdown, Call of the Void) immediately after getting Reaper Form; let them accumulate stacks while you survive.
3. Monitor enemy HP relative to current Doom stacks each turn — when stacks reach within 5-10 of enemy HP, prepare End of Days or Scourge for the next turn.
4. Use Delay and Defy to interrupt enemy attacks in the final setup turn when the kill is one turn away.
5. After each kill with Reap, restore HP and immediately redirect the Doom accumulation toward the next target.

• Highest: Reaper Form, End of Days (build enablers)
• High: Countdown, Scourge (Doom engine)
• Medium: Delay, Defy, Reap (survival and recovery)
• Low: Any card that neither contributes to Doom nor helps survive setup

• Reaper Form costs significant Energy or HP when played — plan the turn you activate it carefully; do not play it when you also need to generate heavy Block that same turn.
• The Reaper kill condition is binary: either conditions are met and the enemy dies instantly, or they are not and you are exposed. Never attempt the finisher a turn early.
• Multiple Doom sources stack additively — Countdown plus one active Doom card per turn can double the accumulation rate compared to passive alone.
• In Act 3 Boss fights, enemies often have mechanics that reduce incoming debuffs or reset HP. Verify the Boss does not have Doom immunity before fully committing to the Reaper plan.