Gennai

Gennai is a probably servant of Azulongmon. He is a humanoid of the digital world, that with his comrades, made the first digivices of Digimon Digital Monster series. But, Piedmon attacked his base, and after, Myotismon used his castle as his base in the Digital World.

In the second movie, Gennai helps Agumon, Gabumon, Patamon and Tentomon to fights against the mysterious virus digimon.

In Digimon Adventure 02, he helps Tai and the others to uses ultimate evolution (He gets youth). No one knows he born as a old man, and gets young, or ever was young, aged and rejuvenated again.