My Coworker Has a Secret! manga volume 2 features story and art by Mushiro.

Akari is an average 25-year-old office worker who harbors a secret she hides from her colleagues; she's a huge otaku, to the point that her obsession is ruining her financially! When her lunch is stolen by a pigeon, a kind, attractive stranger offers his homemade bento in its place, and after graciously accepting, Akari tells him the reason she's so destitute. Of course, she assumed she'd never see him again... but he's the newest hire at the company where she works! Will he keep her secret? And will she learn more about this kind-hearted man?