Luka

Luka is the second prince of the neighboring kingdom, thus he doesn't have a lot (if any) responsibilities. So he spends most of his time at Teddy's castle, but you can also find him at the capital with Nero. He fell in love with him very quickly and is very open about his affection and courting. But he also understands that Nero has ties to his country and wouldn't try to force him to leave just to marry him. So instead he is just constantly around.

He and Teddy have a good friendship, though Teddy does find him a little annoying (but like in a little brother way)