He first appeared in the first episode of PewDie's Paranormal commentaries. At first Jeremy seemed friendly as Pewdie described Jeremy as "buddy" and "his bitch."
He constantly scares Pewdie by appearing out of nowhere behind him and by "pranking him." Jeremy also enjoys Satanic sacrifices and does them around the house with his "friends," other artist dolls that are identical to him.
In the fourth episode of the Pewdie's Paranormal Let's Play, his group of "friends" levitated before committing suicide.
In Beta 8 Episode 5, Jeremy pops up crucified right in Pewdie's face, causing him to be startled.
He also seems to be behind the summoning of the Iamps in DOOM 3, and the bizarre events in Ib.