we don't know that yet lmao
I feel like some people are getting confuse by what is being said here in the comments vs what is said in the story lol. It was implied that Mono had feelings for Baron and that he might have chased (?) after him base on his words to Lego but it wasn't stated that they were in a relationship or that Baron even reciprocated his feelings. Honestly the story can get very confusing. Even I'm confuse..... It doesn't help that there was a gap between S1 -> S2 and the author is adding more plot points too ╥﹏╥
Just an addition, from Mono's monologue (lol) it kinda feel like his feelings for Baron was unrequited and didn't go the way he wanted it to :( Baron might have rejected him and they part ways or Mono didn't get an answer which is why he's still bitter at what could have been or maybe there was some feelings on Baron's side but he chose something else over Mono which goes back to why Mono is bitter and can't move on at present.
thank you, really :*
but what did Baron do to Mono? They had or have a relationship right, and then?