Pakuyasa is a former student of Sakata Gintoki, whom he designated to the supplies because he is not capable of combat. He might be a projection of Gintoki that Pluto Batou saw during their battle prior to the series.
Pakuyasa greatly resembles Sakata Gintoki especially the hair and clothes during the Jouishishi war where he has a white headband and a white yukata. He has a permed silvery-blue hair, an angry pair of eyebrows and a double chin. He looks like a fatter version of Sakata Gintoki.
During Pluto Batou's recollection of his past battle with Sakata Gintoki during the Joui War, it was revealed that the person who fought against him was Pakuyasa. Before the Joui War, Pakuyasa wanted to be Gintoki's student, however Gintoki said that if Pakuyasa really wants to be his student, Pakuyasa has to buy some yakisoba bread for him. Later, Pakuyasa was put in charge of supplies as Gintoki figured that Pakuyasa wouldn't last a minute on the battlefield. As Pakuyasa has no talent with a sword, he quickly left the battle and opened up a candy store named Shiroi Onibito (White Onibito). After getting sued by someone, he opened another store named Shiroi Pansuto (White Pantyhose) and was arrested for public indecency. Currently, he's doing shady part-time jobs. During the battle, it was revealed that Pluto Batou didn't fight with Pakuyasa, and instead fought the murderous intent behind Pakuyasa that Gintoki threw.