... Ryan did completely unneeded stuff I know that he is considering "the threat Kyon has to Lucaon" but still the Kyon that attacked Lucaon was only the other guy (forgot his name) controlling Kyon so he didn't and definitely will not do that out of his own will so it was better if they didn't remove the mark thingy that was the proof of them being servant and master cause that way Lucaon could've controlled Kyon if he got controlled (am I right?) and the best thing is Lucaon knowing about everything BUT from Kyon's mouth and not some servant or Ryan's so that he could believe in him (in case he couldn't believe in him Lucaon would be the one at fault here cause he didn't trust Kyon that much) and Lucaon looking over Kyon so that he wouldn't bring harm to anyone while being controlled.
"キャパ” read kyapa (or kapa) and means capacity "ちいせーんだろうな” read chiiseen darou na and means is really small(or low) and it basically translates to "his capacity is really low"
btw forgot to say the line before it but the whole line "柴ちゃんってキャパちいせーんだろうな” read shiba chan tte kyapa chiisen darou na and means "shiba-chan's capacity is really low"