Shizumaru made his first appearance in Samurai Shodown 3.
He wields an umbrella and a sword as his weapon of choice.
He is a young amnesiac boy who doesn't remember his real name, mainly because he was deemed as a ogre's child since his childhood. So he travels to find a demon hoping to figure out for what it means to be a demon.
During his travels he met Haohmaru who taught him to philosophy of the sword, because of that he respects him.
Later on he encountered Zankuro, you know the guy who committed countless massacres.
So Why does he want to kill Zankuro you ask? well consider that Zankuro was the one who killed Shizumaru's family, Yeah that's a pretty good reason for revenge.
After a long battle Shizumaru slays Zankuro finally avenging his parents.