You can read more about Trejo and the rancor keeper here.
Stephen Root as the Water Monger
Stephen Root plays Lortha Peel, the water monger. He’s a prolific comic actor seen in Office Space, Succession, and Seinfeld, among many other live action and animated appearances. He also can now claim both “Star” franchises, as he played a Klingon captain in Star Trek: The Next Generation.
Sophie Thatcher as Drash the Biker
Thatcher plays Drash, the leader of the swoop bike gang. She also stars in Yellowjackets, one of the best shows currently airing on American television.
The beast in Return of the Jedi was in fact an intelligent and emotionally complex creature, the rancor keeper explains.
Witches of Dathomir
Rancor mounts aren’t entirely new: both Star Wars canon and Legends feature Witches of Dathomir forming bonds with and riding rancors. As well as appearing in now non-canon books, the Witches feature prominently in The Clone Wars.
Paar’s Ichthyodont and the Star Wars Holiday Special
When Boba says he’s ridden bigger creatures than the rancor, he could be referring to the Paar’s ichthyodont in the Star Wars Holiday Special. This animated sequence, which marks Boba’s Star Wars debut, is considered the best part of the infamous special.