Sasaki Isaburo is the commander of Mimawarigumi, who shares his name with the leader of the real Mimawarigumi, Sasaki Isaburo (佐々木只三郎). He is known as the "Triple threat" master of three weapons: the swords, gun and the pen.
He wears a white version of the Shinsengumi uniform but he also wears a long trench coat.
Sasaki Isaburo born into the elite samurai family Sasaki as the main heir. He is also the half brother to Sasaki Tetsunosuke.
As a newly establishled organisation, they have accomplised a lot more than the other police force. Even the Bafku relies heavily on Sasaki Isaburo and the Mimawarigumi.
His personality is completely different compared when using email, he insist people to call him Sabu-chan. He states that he doesn't have many friends.
Sasaki Tetsunosuke: His half brother, he sees him as the Sasaki family failure.
Imai Nobume: His vice commander, Isaburo trusts Nobume abilities as a assassin.
Sakata Gintoki: Isaburo views Gintoki as his favourite email buddy.
Hijikata Toushirou: Isaburo claims he is a big fan of him and Shinsengumi.
Takasugi Shinsuke: Currently not much is known between the two but there is no hostility between the two and they seem to plot together.
His first appearance was in the Mimawarigumi arc, he sent his brother Sasaki Tetsunosuke into the Shinsengumi.