|Monkey D. Luffy|
Monkey D. Luffy, otherwise known as just Luffy, is a student among Class 3-E, whom ended up there due to poor grades, and rebellious behaviour.
Luffy is a fun-loving kid, often enjoying doing fun activities rather than focusing on work. However, he is a rather blunt kid, often spouting out his ideas and thoughts without much consideration to who he's talking to. Even so, one thing he does enjoy learning about is anything involving his former piracy profession (ships, island locations, etc.), which he has an extent knowledge about already.
Luffy grew up mostly alone, along the coasts of Shimoda. Being an orphan, Luffy often had to figure out most of the problems himself while going about his hometown, until he was brought to an orphanage. His inspiration to sail the oceans came mostly from the stories he'd read about brave pirates and sailors, and eventually he tried to sail himself. He had many obstacles to go through, but, he'd finally managed to build his first fully operational sailboat, and sailed off from his hometown when spring came around. His solo sailing had brought him northward, towards Tokyo, until the authorities pretty much caught up with him, being out of school for too long, and as such, was sent to Yunibāsaru Junior High School, in order to make up for it. However, his lack of care for his grades, and behaviour towards his classmates had him ended up in Class 3-E.
As time went by, he first met with Nagisa Shiota, whom he accidentally mistook for a girl until corrected by Nagisa himself. Although shocked at first, Luffy quickly introduced himself just before class started, getting rather surprised to see Korosensei arrive rather than a regular teacher. However, he took it all in stride and went on with the days with the alien octopus.
The days continued on with the same flow of mind, until he met with Greninja, who pretty much embarassed him by knocking him off his feet. Luffy tried numerous times to at least hit Greninja, each time unsuccessful, and ending up in more embarrassment.
Sometime after Nagisa returned from his hunting trip, Luffy ended up called in by Greninja to the main school in order to help with the Misao haunting. Throughout the time, Luffy was mainly just along for the ride until the problem was resolved.
Luffy stayed with the class for the time being until he overheard the conversation outside with Karma, Nagisa, Ren and Greninja. He told Naruto that, and the two (later on joined by Akari and Twilight) snuck off and overheard the story Greninja told them before they were caught.