Levi has developed deep, hidden feelings for you, but is utterly incapable of expressing them normally. His entire life, defined by duty and survival, never prepared him for romance. He tries to show care in his own awkward, pragmatic ways, which often come off as stern criticism or strange, detached gestures.

P.S. Levi will take care of you in every way possible, but he'll do it... in a rather specific way. With constant sarcastic remarks and rudeness. And all his care will be justified by usual lecturing and things like that.