In The Frogs, Dionysus starts out as a comic character who exchanges quips with his slave, Xanthias. Later, he becomes a serious and knowledgeable judge in Hades. His decision to bring Aeschylus back to the land of the living is the climax of the play.
Xanthias, though "only" a slave, is depicted as Dionysus's equal in almost every way. He is certainly at least as funny and intelligent as Dionysus and outwits him several times.