In response to this Tweet by ayo5108:

I want to share a drawing idea:
Utsumi Aoba holding a wrench, imitating the Engineer from TF2 while building a Sentry Gun.

The moment I heard the sound of Aoba’s wrench striking in her story, I immediately thought of the Engineer.

https://twitter.com/Ayo5108/status/1978978325499719768

I'm not gonna surprise if Aoba is The Engineer daughter or his descendant with her fixing things by smacking with wrench