After indirectly killing Glossaryk, he sets his sights on the Butterfly Castle. He then took over the kingdom of Mewni and publicly banished River with his Levitato spell. Luckily, thanks to Star, this didn't last long and he agreed that Toffee should be exorcized from his wand hand when Star stated that Toffee is controlling him. After being spit out by a now-restored Toffee, he was visibly crushed when Toffee denied him any part in the act. Later, when Toffee was reduced to bones and flesh, Ludo retaliated and killed what's left of the villain. He then is pushed to the other dimension once more only more willingly as he asks Star to do so because he needs to do some soul-searching.
Ludo is a pale green pint-sized bird-like monster with sharp teeth, and what seems to be a dark green fringe surrounding the center, making Ludo resembles to that of a kappa.
In his debut, he wears a dark pale green robe with two small skulls, a bull skull with several teeth as a helmet, and flip-flops worn under his robe. Ludo is also seen wielding a black long "wand" with a green eye and dark bat wings.
As of season two, particularly the episode "Ludo in the Wild", Ludo now grows a beard tied in three tails, wears a yellow potato chip bag, and holds a different wand, consisted of a skeleton arm, rock, and the half broken crystal, which originally come from Star's wand after the events of "Storm the Castle".
- He is voiced by Alan Tudyk, who also voiced Turbo/King Candy and The Duke of Weselton. He is even similar to the former, as King Candy and Ludo are diminutive rulers who are insane and childish.
- Even though he is small, he still has a number of henchmen who are much bigger than him.
- Ludo was the main antagonist for the early part of the first season, but was ultimately ousted by Toffee (who then took over as the main antagonist for the series), thus making him a Disc One Final Boss. Ludo took back this position in Season 2, but Toffee took over again. In the special, Battle for Mewni, he redeemed himself and Toffee was destroyed leaving Meteora Butterfly to take their place.