[Crossover] A Brother-Con's Obsession

[Provisional Blurb] A longing that even death cannot take away: Even after forgetting himself and his original purpose, he still never gave up. "There's someone very important to me. I've lost him, and if I don't hurry back, he'll definitely start crying." "Even if I forget his name and what he looks like, I'll recognize him as soon as we meet again." "Why? Because you're my little brother." Reader's Guide: A sweet, satisfying, lighthearted, healing story, with some alternate-setting details. If you're interested, try guessing who the younger brothers are ^_^