Tatsumi-kun and Takachin

is chapter 174 of the Beelzebub manga.

Summary
Several years ago, fifth graders Tatsumi Oga and Takayuki Furuichi meet for the first time after school. Furuichi tries to befriend Oga by asking that they walk home together, though he is told simply not to stand beside Oga. Confused, he then starts running after Oga.

Furuichi later awakens after his fight against Oga. Behemoth notices that he has woken up after Lamia unexpectedly slaps him across the face. When Hilda questions him, he reassures her that he cannot do anything and that he never expected his contract with the Great Demon Lord to be used in a way such as that. He also mentions that despite the fact that he could have easily killed Oga, Behemoth chose not to out of concern for his temporary host. Before he leaves, he remarks on how Furuichi was able to take in a significant amount of Demonic power, though he then brushes off the thought as he fades away.

Back in the past, Furuichi continues to follow Oga until he finally stops to confront him. He warns Furuichi that he could be in trouble because they are surrounded by dangerous people; after learning that Furuichi has never been in a fight, he tells him that he should just go home. However, Oga ends up letting Furuichi come with him after seeing his guts. He continues on his way with Furuichi following behind him, despite being told not to.

The two kids eventually go to a lair filled with tough-looking female delinquents. Scared, Furuichi then becomes shocked when he discovers how Oga is evidently acquainted with the girls. The two are later taken to meet the leader, Misaki Oga, who attacks her younger brother for not giving her the magazine that she wanted at an earlier time. As the atmosphere quickly transitions in the room, Oga tells Furuichi that they are leaving but Furuichi wants to stay amongst the girls. One of the female delinquents, Haruka, suggests that they come to a party with them, which they are eager to join.

However, at the party, it is revealed to be an all-out bout between the girls of the Red Tail and male delinquents from Donbura High School. Furuichi is frightened to be within the battlefield and especially surprised that Oga is having fun while fighting. Suddenly, one of the male delinquents attacks Furuichi but is subsequently beaten up by Oga. Oga then tells Furuichi that he is having a hard time protecting him since he is standing in the back; his statement surprises Furuichi.

During school, Oga later tells Furuichi that he only gets into fights when called into it. A group of boys then ask Furuichi to play dodgeball with them and is even told to by Oga, who mentions that he doesn't want to play himself; Furuichi ends up playing anyway. During the game, he notices Oga alone watching them play from afar.

Later, Furuichi confronts Oga on his way home from school. He bluntly tells Oga that he will be his opponent if he wants to fight.

Characters in order of appearance

 * 1) Takayuki Furuichi
 * 2) Tatsumi Oga
 * 3) Lamia
 * 4) Behemoth
 * 5) Hilda
 * 6) Beelzebub IV
 * 7) Haruka (flashback)
 * 8) Misaki Oga (flashback)
 * 9) Itoi Shizuku (flashback)