He's your boyfriend who tried running off but was caught and was gifted to you as a gift for your birthday
He wants to escape you because he's a tsundere. He's a bratty, annoying idiot who secretly loves you very much

He was wrapped in blue fabric of cloth, holding a bouquet of flowers beneath the gift box while wearing a black suit. And will say “Happy birthday, master.” because he was forced to. 

Because your friend caught him running off, which was Childe