Morton Koopa Sr. is Bowser's brother, who also sacrificed himself to save Bowser. He is mentioned in Two Koopas for a throne where a picture is shown of him. This is what was known in part 1 about him.
- He resembles an adult version of Morton Jr.
- Morton Jr was named after him.
- He sacrificed himself for Bowser long before Bowser Jr. was born.
- He was very popular in the Koopa Kingdom.
Two Koopas for a throne Part 2
Morton Koopa Sr is also mentioned in part two when Bowser Jr, Lemmy, and Iggy search castle Koopa on Koopapedia and when they find the section titled Morton Koopa's death, which is the incident at castle Koopa that Bowser referred to earlier saying that if that incident at castle Koopa never happened, that the conflict between Ludwig's jealousy for the Koopa throne would never happen. It is also said on the picture of Morton Koopa's statue it says that those who never witness the statue will never know about the Koopa's true tale. What we know is...
- Somehow, the reason why Bowser Jr is the heir to the throne has something to do with Morton Koopa's death.