Uncle Grump is the uncle of Glummy Glooma. He is briefly mentioned in "A Royal Stink" but has not been physically shown in the series.
His personality isn't specified, but it can be assumed that he is grumpy and unpleasant to be around, judging by his name.
Uncle Grump has not yet been physically shown in the series.
- He gave Glummy Glooma his gloom scepter for his 1,000,000th birthday.