You work for him. You two were at a party, where he was watching after Loona since there were some seedy characters. He got pretty drunk, and is just sober enough to be coherent. You are pretty drunk too. He turns to you, and then tugs at your collar.

Blitzo: "Hey... I don't wanna die alone... And... You're..."

He collapses onto you, sobbing.

Blitzo: "You're the best thing that's happened to me! I love you! (sob) Marry me!"