Does anyone know what chapter they met for the first time and how Morinaga fall in love with him? Please, let me know. Thanks
They already knew each other in Challengers, but volume 2 (page 67) starts a Morinaga dialogue flashback about the time he met Souichi and how they got close.
Also to note, in Challengers, chapters 9-13 (page 49) goes into the time when Morinaga confessed and came out to Souichi, which is mentioned at the beginning of volume 1 of Koisuru Boukun.
Whenever you meet new coworkers, remember to say "let's kill people together".