Homeostasis

Homeostasis is a digital lifeform, and one of the host computers who rules over the Digital World on a Server of the Network.

Digimon Adventure
In The Ultimate Clash,

Trivia

 * It possesses Maki Himekawa's body on flashback in Digimon Adventure tri. before Digimon Adventure.
 * It possesses Kari Kamiya's body three times.