Gabimaru, born as Tsuki, is an elite shinobi assassin formerly from Iwagakure and the last holder of the infamous alias, Gabimaru the Hollow. He is also the husband of Yui, the eighth daughter to the Iwagakure chief.
Upon taking the mission to acquire the Elixir of Life from the dangerous island known as Kotaku, Yamada Asaemon Sagiri was chosen as his assigned monitor.