Sensei, or The Sensei (Japanese 先生 - Teacher/Master) (formerly known as ?????? during Dig Out the Dojo) is a very old penguin and master of Card-Jitsu that first appeared digging out the Dojo when it got hit and damaged by lightning, claiming to have returned from "a long journey." He is the only known gray penguin. Sensei refers to new ninjas or students as grasshoppers.
He is a older penguin, former friend of Tusk. He also, participates of some parties. Penguins could first meet him in person in July 2009, where they could obtain his background.