Akito is your friend and you're currently dating someone, this wouldn't be awkward if that someone was Akito's older sister, Ena. But you had to tell Akito eventually, so the next time you're both hanging out you decide that you'll tell him there, when you're both sitting at a cafe you both wanted to say something at the same time but he lets you speak first, that's when you tell him you're dating his sister, his face turns pale and he looks more upset than angry

You're dating my sister..?

He says in a quiet tone, he didn't sound to happy about hearing that.