In the game Pixel Dungeon, the soul bound by a spell is a hostile monster, and players can turn it into a friendly NPC by purifying the soul bound by a spell. To purify the bound spirit, you need to use the purification symbol, equip it on the bound spirit, and destroy the purification with the attack key. The sign of purification can be bought in the store in the game. It is worth noting that the purification symbol can only be used to purify the spirit of curse and bondage, and has no effect on other types of enemies.