Encounter with Vox Machina
Juurezel had infiltrated the palace of Sovereign Uriel Tal'Dorei III in Emon. He revealed himself to Vox Machina after they banished the shades from Uriel's family, introducing himself as a devil prince, and told them of a great war between devils and demons that was spilling over into the Material Plane and threatening all of creation.
He justified his actions by pointing out all of the demonic activities Vox Machina had been dealing with since entering Emon, and warned them that horrible devastation would ensue if they stopped him. The party believed him, and Juurezel requested their assistance in destroying the demonic threat, offering a single Wish spell should they make a pact. After some deliberation, the party agreed to the contract.
Vox Machina left, but began thinking over what they had just agreed to. They returned to the throne room and asked Juurezel to provide their Wish to aid them in their demon-hunting. Juurezel agreed, and the party used the Wish to cancel their contract with the fiend and attack.
Furious, Juurezel revealed his true form as a glabrezu—a treachery demon—and a long and deadly fight ensured. During the fight, Pike was slain by a critical hit as the glabrezu picked her up in its pincer-like hand and cut her in half. Fueled by the death of their friend, Vox Machina (specifically Vex) then dealt the killing blow to Juurezel.