Where is Castellan Toad?

So i want to kill Castellan Toad for a quest. and like idk how to find him. and if theres a pre queust then can some1 link me?

You have to find your way through the maze of the castle.

Ninja Castle map.

The 10th "Zipangu: Ninja Castle Hallway" map, if you follow Hidden Street's map right, is a jump quest. After that, there's a few more maps until you finally reach the Castellan Toad.

Good luck in the jump-quest xD its a pain hehe and if your unlucky and cannot find one in your channel you cannot change channels. And if u get out of the room you will end up at the very start again. Soooo good luck D:
(Also with killing)