Nubert Nimbo was formerly Uncle Grandpa's biggest fan as seen in the episode The Fan. He is voiced by Billy West.
He's an older man with a moderately out of shape build, large nose, and dark brown hair styled into a page boy cut. He wears a worn orange shirt and worn green shorts as well as sandals.
Nubert is a typical fanatic, obsessive and clingy. He's extremely over protective and particular about the merchandise he collects and the fanart he makes, making sure even his own mother won't touch his stuff. He absolutely adored Uncle Grandpa and his show before Uncle Grandpa messed up all of his stuff. He is currently a huge fan of Xarna.
- Newbert has a Tumblr account on his laptop, and he writes Uncle Grandpa fan fiction.