Osamu Mikumo/Plot

Background
In the past Jin saved Osamu from a Trion Warrior when he tried to sneak into Border HQ. Rinji Amatori was investigating Neighbors during the days before he went missing, resulting in Osamu owing him a favor of looking after Chika for him if he wasn't able to anymore.

Introduction Arc
Osamu is first introduced as a normal 9th grade high schooler. He has been shown to have high morals and is quite willing to sacrifice harm to himself in order to save others from harm despite being quite weak.

Border Enlistment Arc

 * Osamu Mikumo vs. Shun Midorikawa: Loss (10-0)

B-Class Rank Battles Arc

 * Mikumo Unit vs. Suwa Unit vs. Arafune Unit: Win
 * Mikumo Unit vs. Nasu Unit vs. Kuruma Unit: Win
 * Mikumo Unit vs. Ninomiya Unit vs. Azuma Unit vs. Kageura Unit: Loss (Ninomiya Unit's victory)