Off-kai Shitara Tondemonai Yatsu ga Kita Hanashi

Megumi Miki is a loner and a closet otaku who's pretty devoted to her fan activities! She wants a friend who she can gush over her bias with... and when she went to an offline meeting with a follower from social media, they turned out to be a bona fide yakuza!!! Despite feeling like her life is in danger, after talking with him, she could tell that he's a truly passionate otaku! He's overly sensitive, and any talk about shipping the reverse of his faves are a taboo. Plus, he turned out to be the troublemaker that his appearance suggests, but being with him is fun and he's also dependable!!

(Source: Kodansha, translated)