Hattori Masanari

Succeeded his ninja father, Hattori Hanzo, at the age of 18 in 1590 (six years before Hanzo would die at sea in a battle against the Fuma-ryu ninja clan.) According to Stephen K. Hayes, he had not mastered ninjutsu and mistreated the Iga ninja who were (presumably) serving under him during the guarding of Edo castle.

"The ninja did not consider him worthy of the name Hanzo, and the band revolted. Armed with guns and bows, they holed up in a nearby temple and demanded his dismissal. If their demand wasn't met, they vowed to kill Masanari and to take their own lives."

Died in the famous siege on Osaka castle.

Masanari's name doesn't seem to be mentioned anywhere on the net outside of Hattori Hanzo biographies; it doesn't look like history will ever see him as being anything other than his father's son.