Brother Tranquility is a zombie monk from Harmony Island. Players must talk to him to start The Great Brain Robbery quest. Should players attempt to start the quest without the levels required to complete the quest, Brother Tranquility will simply reply stating that the player does not have the levels required.
He stays inside the Harmony Island's windmill during the whole quest, first reason being the Zombie pirates walking outside, second being the sleeping gas enveloping the whole island. At this point, Brother Tranquility asks the player to find a book in the Edgeville Monastery to repel the effects of the gas outside the windmill. Later, he asks the help of a surgeon to transplant the brains in the real bodies, adding the presence of Dr Fenkenstrain in the quest. Finally, his last request is to confront Mi-Gor, starting the fight against Barrelchest.
For those who have lost their Barrelchest anchor, they may talk to Brother Tranquility to get a broken anchor, which can then be fixed by Smith.