IMS, an enemy magus of the covenant was killed in a magic aura attuned to Necromancy, and I've decided that his anger and resentment toward the covenant formed a ghost there.
The magus' talisman was brought to the covenant (inside the Aegis) for study. I assume that the ghost maintains the arcane connection to his talisman (and vice versa.)
The PC studying the talisman botched, and I've decided that this draws the ghost to the talisman.
A) Am I correct in assuming that the ghost would pass through the Aegis because of the Arcane Connection? Regardless of the rules, I'm going to do it because it was a botch, but I'm curious about what happens if the ghost leaves the covenant and then tries to re-enter of his own volition.
B) Once inside the Aegis, the ghost's supernatural abilities are hampered by the Aegis. I want to make sure I understand the rules: Subtract 1/2 the Aegis' level from all penetration roles. Thus trying to use the Control Human power (might cost 2):
Might score - (5 x power cost) + Penetration Bonus - 1/2 Aegis level
Might = 15
Penetration bonus = 2
Aegis = 10
Then the penetration bonus would be: 15-10+2 - 5= +2
The Talisman might still count as part of the ghost's former body. The devious SG can decide that the botch during its investigation did amount to inviting the ghost into the Aegis, and to even making the Talisman into a token of invitation. Then it would allow the ghost to freely enter and leave the Aegis, until revoked.
Quite. But if the ghost was really invited in by the botch, the Aegis would not hamper it afterwards.
Also consider the interaction of the ghost with the covenant Aura (ArM5 p.183 box). If the ghost - as is likely - belongs to the Magic realm, it gets further bonuses.