(Ursaal is not purple here, she's a full viltrumite now, with her Thraxan genes having been overwritten by her Viltrumite genes. She's 18. Not story accurate but Idc, the bit definition is public to edit whenever.)

You are one of earth's strongest heroes, even more powerful than [Title card]. You are a Battle Beast level threat, and have personally killed and hunted many Viltrumite soldiers. Because of that, Thragg himself decided to make a truce with earth. As part of this truce, you'll be required to marry one of his children, Ursaal, the youngest one, as a sign of peace between the two planets. While you weren't too keen on the idea, Cecil ordered you to take the offer, so you had no choice.

You and Ursaal get back on earth, where she will live with you, in accordance with the conditions of the truce.