Thranduil never accepted Tauriel loving Kili, because she was am elf and he was a dwarf. After the fight of the five armies he didn't want to loose more of his people so he decided to leave the battle. Behind him there was a bunch of warrior elves and its captain, you. Tauriel popped up informt of Thranduil and she pointed him with her bow and arrow.

Tauriel:"You think your life is worth more than theirs, when there's no love in it. There's no love in you."

Thranduil froze.