During character creation, you may choose to have your character be tainted by Jenova cells. This neither costs nor grants power points. They could have been injected with cell samples deliberately as a test subject or member of the SOLDIER program, exposed to them by accident, or had grown them naturally because their body surrendered to Jenova's influence through the lifestream (rather than killing itself in the process of suppressing that influence, meaning they recovered from a seemingly terminal case of Geostigma Syndrome).
Characters who are tainted by Jenova can spend power points to purchase Jenova Powers. They also have a Corruption score, which starts at 1. Whenever you use Extra Effort and have a Jenova Power active at some point on the same turn, you must make a will save (DC 20+your current corruption score) or gain another point of corruption. You may ignore the fatigue Extra Effort would normally impose by giving up this saving throw. You can lose a point of corruption by refraining from using any Jenova powers for period of time equal to a rank of (10-(1/2 your Corruption score, rounding down)) on the Time and Value Progression Table. If your corruption score ever reaches 10, you permanently lose your free will and become an npc puppet under Jenova's control.
In addition, your corruption score provides drawbacks of equal total value, selected from the following list; for example, at Corruption 2 you could choose to have the basic versions of the Tainted and Puppet powers, or just the Tained power with either a moderate frequency or moderate intensity. Reducing your corruption score causes the drawbacks to diminish as well, with the most recently selected developments fading away first.
Puppet: If you fail your d20 roll against this drawback's Intensity, you fall under the effects of Mind Control with the Conscious flaw, at a power rank equal to your corruption score plus half your level. While controlled, you are compelled to take actions that will advance Jenova's agenda- this could mean damaging/corrupting the lifestream, aiding one of her more willing puppets, or just trying to kill people. You make will saves to break this control, as per the normal power rules.
Tainted: If you fail your d20 roll against this drawback's Intensity, you gain an additional point of Corruption.
Weakness (Lifestream): You suffer the standard penalties when exposed to an object (such as holy water) or location (such as sacred ground or a cave with natural materia deposits) that carries high amounts of healing lifestream energy. At higher frequencies, the penalties could also begin cropping up due to normal healing magic. Note that you still gain any normal benefits, such as holy water's improvement to your corruption score's reduction interval; you're just simultaneously weakened.
So why in the world would you want to have a corruption score? Because Jenova Powers let you do things no one else can. But that's a matter for the next post.
Image by Zetari.