Wu

" Never put off until tomorrow what can be done today."

Sensei Wu is the teacher of the four ninja, Kai, Jay, Zane and Cole. He is the younger brother of Lord Garmadon and uncle of Lloyd Garmadon.

Background
Sensei Wu is the son of the First Spinjitsu Master, the creator of Ninjago. In childhood, he and Garmadon were the best of friends, until one day when Wu lost his father's katana, and Garmadon went to get it. The young Great Devourer bit Garmadon's hand, and he became more violent, eventually turning evil due to the bite.

After their father died, Garmadon and Wu vowed to protect the Four Weapons of Spinjitsu. Garmadon, however, planned to steal the weapons, but when he tried, he and Wu battled, and Wu won, banishing Garmadon to the Underworld.

Also, it has been said that Wu and Garmadon were once friends with Kai's father.

Appearance
Sensei is an old man with a white beard, a conical farmers hat, a bamboo pole, and a random tea set that shows up at strange times.

Trivia

 * He had the last flute made to stop the Serpentine (Pythor took it).
 * He knows every last bit of info about Spinjitzu.
 * He has never taken off his hat, even when he sleeps.
 * Its a running gag that he drinks tea at the oddest times.(falling to death, underwater, etc).
 * He was swallowed by The Great Devourer, but he survived when the giant snake was destroyed by Lord Garmadon.