Chrollo known as Chomper 

Killua and Gon were captured by phantom troupe and taken to their secret base.

The group confronted Chomper and his battleaxe, the Demon Slayer, to put an end to the Phantom Troupe and Chomper's evil.

With the help of Doraemon, Gon, Killua, Gon's children, and the Nemesis team they were able to destroy all of the phantom troupe members, save for Chomper.

Chomper, having lost his sixth arm during the battle, needed the last arm to keep the Demon Slayer arm and Chomper took Killua hostage, promising to let Killua go if everyone in Japan would surrender.

While a drunken Gon decided to bring Killua home to save his life, Chomper fought the revived Seven Arcs team, but was defeated.

Chomper told Killua that he could either fight and die or let Chomper keep the Demon Slayer arm and be killed.

Killua jumped from the hospital and landed on top of Chomper, showing him the last of his inner self, and said goodbye.

It then shows Chomper being defeated with his face getting thrown onto the ground.

Then the episode ended with Chrollo known as Chomper telling the room that he did what he had to do to save his country and his people, but he will be back for Killua.

Sometime later, Chomper was told by Nemesis team member Suigetsu that Killua was now on his own.

Chrollo known as Chomper by Drapen May 19, 2022