In the middle of a drill, Killer T Cell accidentally tosses a trainee right into Helper T Cell’s office, hitting the commander. The two polar opposites begin arguing.

According to Dendritic Cell, although they play very different roles now, the two were actually classmates at Thymus School. Dendritic Cell also reveals how different both of them were back then!

What could've happened between the two, as they must’ve endured the hellish training days together at Thymus School, where only 2-3% of the class makes the cut!?