Homeostasis

Homeostasis is a character from Digimon Adventure and Digimon Adventure tri.

It is a digital lifeform and one of the host computers who rules over the Digital World on a server of the Network.

In Digimon Adventure, it possesses Kari in order to communicate with the DigiDestined and end the fight between Tai and Matt. The reason it possessed Kari is because Kari was the only one who could acknowledge it.

Years before, it did the same with Maki Himekawa, one of the DigiDestined preceeding Tai and his team, in the original DigiDestined's losing fight against the Dark Masters.

Fire Rebellion: Season 18
Homeostasis possesses Kari to warn Nate that the effects of the Knight Map's damaged state will cause any Human crossing into Equestria to weaken in the same way Zoey weakens.