Mujina

Mujina is a ninja in training, wondering how he would survive. He is not doing so well in the training, just like his father, who was nicknamed "The Cockroach" by everyone. The Cockroach died fighting for his leader, when he was used as bait to be sacrificed during a mission, but not before he passed along his secret technique to Mujina.

(Source: Shogakukan, translated)