Tsuneyuki Okudera/Relationships

Noboru Koarai
Koarai and Okudera are teammates who seem to enjoy a good relationship and a friendly rivalry when discussing strategy in front of Azuma. Due to their differing personalities, Okudera may end up Koarai's more reckless tendencies, and may feel frustrated when Koarai acts smug around him. This however does not diminish the concern Koarai shows for Okudera in combat, and the latter has also demonstrated to care about Koarai's mood. They address each other by surname, without honorifics.

Haruaki Azuma
Azuma is Koarai's captain and mentor. He educates him in strategy while giving him the space to come up with his own plans. In addition, he is to an extent responsible for Koarai's Trigger Set, having forbidden him to equip Sub Triggers until he showed to have grown enough. Okudera greatly respects Azuma and heeds his commands without question. They address each other by surname, with Koarai adding the honorific -san.

Mako Hitomi
Hitomi and Okudera are neighbors, and Okudera has had a secret crush on her since they were children, which not even Koarai has noticed. Hitomi is a big sister figure to Koarai and Okudera, who joined Border when she did, and she may invite them to cool down when their discussions turn into ego battles. He has grown accustomed to finding her giggling while watching horror movies in the dark in the strategy room.

Kyōsuke Karasuma and Mitsuru Tokieda
Karasuma, Okudera and Tokieda are school friends.

Sumiharu Inukai
Inukai knows Okudera well enough to be aware of his prudence, as well as to call him by his nickname without adding an honorific.