Council of Ghosts

Council of Ghosts is an Act 2 event where a group of spectral ghosts appears and makes a single offer: accept and lose 50% of your current maximum HP in exchange for receiving 5 Apparition cards, or decline. Apparition is an Ethereal, Innate card that grants 1 Intangible when played, providing exceptional single-turn damage immunity. The 5 Apparitions effectively give you five turns of near-invulnerability spread across combats.

Council of Ghosts is widely considered one of the best events in the game. The 50% max HP cost is significant but offset by the massive defensive utility of Apparitions, which are often worth more than the HP in practice. Accepting is almost always the correct choice, particularly for characters who struggle with defense or for runs that have taken significant damage. The only scenarios where declining might be correct are if your current HP is already very low and the 50% cut would leave you dangerously close to death.