Possession was an ability where a spirit, usually a malevolent one, took over a living being's body and directed their actions. Marka Ragnos possessed Tavion Axmis in 14 ABY in his bid to return to the material world. While possessing Axmis, he was able to use his powers through her.
Vitiate demonstrated the ability to share his essence with many individuals, transforming them into extensions of his will (known as Children) and embedded these individuals within the enemy ranks to serve as his eyes and ears on a galactic scale. In addition, during the Ziost massacre he was able to possess nearly all sentient lifeforms on the planet.