As harshly as Zrozex put it, he's got a point.
Assuming the astral does contain beings one could label as "evil," who are you and your group to stop them? The astral is huge and I'm willing to bet that you are younger and less mystically practiced than most of the so-called evil living there.
Further, how have you concluded that the evil needs to be removed? Several times in human history we've decided we don't like some species or kind of species and then erraticated it much to the detriment of the eco-system. However unpleasant or unsettling it may be to share the astral with demonic or evil beings, maybe they belong there. How would you know? However noble a concept, you may ultimately end up brining great harm to the balance and nature of the astral and doing a great disservice to those beings whose karma had sent them to be evil astral denizens.
And finally, you really named it after a video game? This repels experienced practitioners aiming to avoid fluff and draws in fluffy morons who want real life to be a video game. How do you honestly expect experienced adult magicians to want to join a group based on a piece of primitive modern fiction?