Warlock

The name Warlock refers to the sword, not the wearer. Per the in-game text, the weapon is bound to a devious demon familiar and grants immense power while dragging its wielder into terrible incidents and trying to take their life. That setup shapes the aura: the Sol's RNG Wiki describes the player levitating in strong magenta light and smoke, with a grinning, horned entity floating behind, its hands extended and its fingers moving in sync with the player's motions.

The entity's tail wraps around a large hovering sword with a glowing eye set in the center of the hilt, facing outward. Purple particles and wisps rise from the ground, pink energy rings pulse out from the player's position, and pink flames burn around the player and the entity's head and hands, giving a hellish impression.

It is a Legendary from Eon 1-5 at 1 in 666,000 with no biome requirement, so a 10x potion brings the expectation to about 66,600 rolls. rocca1080 is credited, and the aura sits close in rarity to the Hell-based Devil variant, though it can be rolled anywhere.