"Liom" is possessive. You are saying it belongs to you. So it is "mine" not "me"
so if is liomsa é translates as 'he is mine', how does one say 'I am his'? Would that be 'Is leatsa mé'?
That would be "I am yours." I suppose one could say, "Is leis mé," but I amn't convinced that's a construction one would use about people.
Is there another online resource that has this possessive pronoun in its forms? It's hard remembering liomsa and leatsa, etc.