ULTIMATE PLOT THINGIE

What Tali is after is an ultra-famous ancient, mythical Talisman called simply The Elder Star. Nobody knows for sure what it looks like, or even if it really exists, but Light Sorcerers believe that if a person with a pure soul can master The Elder Star, that person reportedly becomes nothing short of omniscient, able to see past, present and future, and how the three weave together in Eternity. That person can even alter fate. If someone with an evil spirit tries to use it, it devours their soul. So to use the thing you have to have the soul of a saint, and your motives in attempting to use The Elder Star must be pure and completely altruistic.

That's what the good guys say it can do. The bad guys have other theories. Dark Sorcerers believe it's a weapon with the power to alter fate at most and blow up huge chunks of the countryside at least. It can also reportedly enslave the souls of others to the one who masters The Elder Star. Naturally, their theory says nothing about it devouring the souls of those who try to use it for evil purposes.

The bottom line is, no one is really sure what the Elder Star is, what it does, or even if it really exists. But both Good and Evil are betting that it does and neither is willing to let the other get its hands on something that powerful.