Certain creatures can attempt to possess characters, taking over the character‚s body entirely. First, when a creature attempts to possess someone, he must make a Possession check against the defending character‚s Will. The creature‚s entry will detail what the creature‚s bonus to this check is, as well as other details (such as maximum range of the possession ability).
If the possession check beats the character‚s Minimum Will, he takes a morale penalty (untyped damage).
If the possession check beats the character‚s Will, the character is possessed. Now the defender and possessor have equal control over the character‚s actions. On their respective turns, they can direct the character‚s body to act. However, the body can‚t act for more than six seconds per turn, which could be three seconds each from the possessing creature and the possessed character, six seconds from one and none from another, or any combination thereof. Whoever is currently controlling the character uses their own skill bonuses and techniques, their own mental ability scores (intelligence and spirit) but the possessed character‚s strength, endurance, and dexterity. Acting characters can use only their own combos and cast only spells that they know.
Either of the actors involved can attempt to veto the other‚s turn. To do so, make an opposed Will Check (1d6+Will). If the acting character wins, he has control for the turn and the vetoing character takes a morale penalty. If the vetoing character wins, the acting character‚s turn is skipped. In cases of a tie, roll again. A character with zero Will cannot attempt to veto.
In this example, the fell demon Bal-Ziggaroth attempts to posses the hero Jack Clancy. First Bal-Ziggaroth makes a Possess check (his bonus is +4) against Jack‚s Will (9/3). Bal-Ziggaroth rolls a 6, meaning his total Posses check result is 10, so he succeeds. Jack is now possessed.
Bal-Ziggaroth acts before Jack in the initiative count, and decides to use Jack‚s body to shoot one of his comrades. Jack, wanting none of this, decides to veto Bal-Ziggaroth‚s turn (risking a morale penalty in the process). Each makes a Will check (1d6+Will). Jack‚s Will is only 8, while Bal-Ziggaroth‚s Will is 11. In the end, Jack only got 12, while Bal-Ziggaroth got 14. Jack fails his veto, takes a morale penalty (dropping his Will to 7/2), Bal-Ziggaroth is able to control Jack‚s body for his turn. Bal-Ziggaroth shoots Jack‚s friend using one of the demon‚s own combos (taking four seconds) and takes no actions for the remaining two. On Jack‚s turn, he has two seconds to use (which Bal-Ziggaroth can attempt to veto).