Maeda Sanza is a Captain of the Surprise Attack Division, a group of ninja who use the element of surprise to attack enemies. He first appears in Stage 2-1 of the Special Jounin Campaign (Hard Mode) as the scouting team and he took the main character with him for the team since Yudai relies on the main character's abilities.
Later, after the main character defeats Akazosu, Maeda tells the main character to report back to Yudai.
