[Balanor]

Did you actually select Mask as your patron god through the Player Menu > Player Guide > Gods & Religion? Due to the fact that really anything can be entered in the Deity field at character creation, this is a requirement to make sure that the right spelling and a valid god is in that field before you can perform deity-related 'stuff'.

If so, then reason you were able to join the 'Temple' of Mask without having selected one is because you have rogue levels...