Master Kriosos (Jiro Krisosos) is the Paternal-Grandfather of Yamato Kriosos and the Leader of the Kriosos Family. He is a minor antagonist in the Ninjago series. He resembles Sensei Wu, but evil.
Jiro Kriosos was one of the Students in Wu and Garmadon's school who did not tolerate Wu's decendincy from the First Spinjitsu Master and being a son of an ancient like him.
Jiro trained many of his decendents like (Yamato) Evil Spinjitsu to outsmart the allies of Wu and his decendents like Kai.
- He has the Powers of Darkness