Gamaken

is a giant toad that was summoned by Jiraiya during his fight with Pain. He wields a sasumata-like weapon and a shield. He also seems to be wearing the same robe as Gamabunta. He is constantly commenting on how stupid and weak he is.

Personality
He is constantly refering to how clumsy he is, and constantly seems nervous, albeit he also says he will do his best. Like most other toads he has no real respect for Jiraiya, and when scolded about ruining Jiraiyas pose, he just responded by saying that it is not his fault, but Jiraiya's fault for being klutzier than a drunken monkey.

Infiltration of Amagekure
His first and only known summon so far was by Jiraiya, when he was facing the Akatsuki leader Pain, and decided to use the Sage Mode. However in order to use Sage Mode, it would take him some time to prepare it, and he could not effort to take the risk of leaving himself unprotected, so he summoned Gamaken. During the time it took for Jiraiya to prepare the technique, Gamaken was forced to face of with great variety of Pain's various animal summons and was kicked back and forth throughout the tower they were in, until he was pushed into a sewer where Jiraiya told him to return as he was finally finished.

Abilities
Not much is known about his abilities, only that he is sturdy fighter with great deal of defensive cababilities, and that he seems well verged in using his shield and staff weapon, while still being able to protect a human standing on his head.