Just to be sure, are they half brothers or what?

MC's the son of the king and the ML is a distant relative of the king

Pretty sure the only reason seme calls uke “brother” is bc the emperor (uke’s dad) took him in for a time while he was young bc seme’s dad died and they lived together, practically siblings

Omg help thank you, i almost thought that the duke was the emperors love child I-