Heya, let me yap about my merboy lore a little :D
Sol was born in the ocean (he prob also has siblings, but I'm still considering this). So, the thing is, he was born mute, but he still can hear and properly understand other's speech, so he communicates either with notes (that is not always convenient, bro lives in the ocean there are not so many surfaces where he can write), or with sign language (I thought about what if merfolk have their own sign language like different countries has theirs lol).
Because of his muteness he had pretty few friends back in his childhood, but he was able to focus on anything better than other mers in his age, and it was one of not so many pros in his "feature".
He's willful and bad at expressing emotions, but pretty smart and chill in general. If we're talking about his job for now, he is like one of royal guard, I think. That's kinda why he has that harpoon-like coral weapon with him on the ref. (Fun fact: this harpoon wasn't even planned, I just couldn't find a good position for his hands for the first time when drawn him😭)
