
I can't read Japanese but I'm pretty sure
(Spoilers)
That Ile never left Alta in the first place. After what happened to him during their escape attempt, he gets sent off to a remote village and is stationed to work there. He gets into an accident(getting hit by falling rocks) and ended up losing his memories. When he and Alta meets again, it's up to Alta to bring Ile back and showing him that he really loves him

It's true but what I mean was, Ile has followed the order and leave Alta from the first place. He should do something about that but he didn't even though he promised Alta to never leave him. Instead, he still following the order and went to the village and got the memory loss. :( .. it just too sad.. sorry if i was mistaken (/TДT)/
SPOILERS maybe? Alta, best Uke!
Ile left Alta because he never knows that Alta loves him romantically. He mistakenly thought Alta was bound with him just like a child loves his mother, but Alta loves him romantically. Alta is a very strong-will uke. Alta never stops loving Ile even though he left him. He always believes that one day he'll be together with Ile and need to be strong till that time has come. He is the most brilliant character in this series. Look what has he done with his hair.
Prince Togato is the uke. You guys don't have to worry. He actually is a kind person but he acts harshly because he was jealous of Alta and Ile. The person he loved (also a white hart) have been paired with his sister, not him. He couldn't fight the order. When Alta has strongly rejecting to get married and Ile stand strong behind Alta defend their love, Prince Togato pissed off. He wishes that he and the one he loves could be like Ile & Alta. Aside from that, Togato truly cares for Alta. He doesn't want Alta to end up to be hurt like him (unrequited love).