From Dragalia Lost Wiki
Hell's Melody is a special effect that changes the enemy's affliction resistance. It is currently only used by Iblis.
- If Iblis is Water-attuned, his Stormlash resistance will be set to 0.
- If Iblis is Shadow-attuned (phase 2 of master), his Flashburn resistance will be set to 0.
- A counter will be displayed on the ability icon, and will decrement by 1 for each time the relevant affliction is applied to Iblis. The counter's starting value depends on the quest:
- Iblis's Surging Cascade (Rise of the Sinister Dominion)
- Iblis will periodically check the counter on the current melody.
- If the counter is at 0 when checked - Iblis will switch the melody to the other one ( Heaven's Melody).
- If the counter is NOT at 0 when checked - Iblis will reset the counter to its maximum value, cast Corrosive Marcato (inflicting Creeping Corrosion on the party), and give himself Strength Up and Defense Up buffs with infinite duration (requiring Dispel to remove).
- On Master and Legend difficulty, Corrosive Marcato will instantly kill the entire party.