My Love Story with Yamada-kun at Lv999 manga volume 1 features story and art by Mashiro.

College student Akane has just been dumped by her boyfriend. Heartbroken, she decides to quit the online RPG they used to play together, but instead of deleting her account, she logs in and battles low-level enemies to relieve her stress and hurt feelings. There, she meets Yamada, an elite pro gamer so reclusive that Akane can't decide if he's awkward or alluring.

When Akane encounters her ex at a gaming convention, she makes the snap decision to pretend Yamada is her boyfriend and soon the two of them are spending time together both in the game and in real life. The problem is, Yamada is only interested in the game. As Akane's feelings grow, will Yamada's focus stay on the game?