Does anyone have ideas how and whether a priest's ability to turn undead, Tanar'ri, Baatezu and others works in Sigil? I am currently running a campaign where this question has come up. I haven't found any information on this in any of the 2ed ps books. Related to this topic I have only found the statement that banishment doesn't work if a creature is encountered on it's home plane.
As far as this concerned I have decided that the priest's ability to turn undead works normally in Sigil and this should not be an ability that is affected by the Gods limited power in Sigil. As the only way in and out of Sigil are the Lady's portals it seems to me that the priest's ability to turn Tanar'ri, Baatezu and other lower planar creatures cannot work properly though. A priest might be able to turn a Tanar'ri or other creature but he/she cannot banish those creatures as there is no link to the Astral or Ethereal planes from Sigil which would be necessary to force the creature/s to it's home plane. [Just in case someone is not familiar with the issue: Just like a priest is able to turn or (in the case of lesser undead) destroy undead a priest can also turn or (or in the case of lesser Tanar'ri, Baatezu etc.) banish lower planar creatures back to their home plane] Banishment would therefore not work in Sigil.
Does someone have any more information on this or knows about information in one of the 2ed ps books. Any feedback is welcome.
Just because the gods can't enter Sigil doesn't mean you can't channel energy- that's what a clerical spell is, after all. Banishment would fail, for the reasons outlined- just like you can't planeshift. Turning undead (and outsiders) would work as normal though.
You couldn't (as far as I know) turn anything besides undead in 2ed, and turning worked normally in Sigil. (Or at least nothing every said it didn't)