Thor chuckles at Loki's ire, laughs at his bitterness because what else is there to do? There's no point to getting angry and he finds it hard to be so, not when Loki sits there bleeding and petulant like a child angry that he's lost a throwing dagger competition. (Something that, of course, has never actually happened to his brother.)

"Will you want my help, brother? Shall I take you someplace to rest?" There's concern in his face, honest and unguarded, and his hand shifts from Loki's wounded and bloodied shoulder up to his neck. He cups it as he has many times before, back when 'brother' had been a term of endearment and not a mock.

He smears red across black hair and pale skin, and it's a fitting visual for the mess their relationship has become.