Delrith

Delrith is the demon summoned to destroy Varrock in the Demon Slayer quest. He is combat level 27 with 7 hitpoints.

History
150 years ago the Druids of the Varrock Circle split off from their Taverly brethren and became Chaos Druids. After corrupting the Circle, the Chaos Druids summoned Delrith, who laid waste to most of Varrock. Eventually a hero called Wally defeated him with Silverlight and sent him back to his own dimension.

Demon Slayer
A cult of Dark Wizards have summoned Delrith to destroy Varrock again. This summoning and Gypsy Aris's foretelling of it is the start of the Demon Slayer quest. Once a player attacks Delrith with Silverlight, he takes the form of "Weakened Delrith", in which the player would recite a spell to seal him into abyss to complete the quest. Delrith can only be fought once.

See

 * Lesser Demon