Most immortals have hints in their helpfile. Sounds like you have been playing for a while, so you should have at least the general knowledge to find them.

Even if you don't, you can also ask around in game.

"who sphere" tells you everyone with the same sphere. They might know.

Obviously someone else in your religion would know.

Just random strangers would know too. For instance, I now know (I think) every active shrine in the game. Aside from the new guys, and I have a good guess on Akresius, just haven't looked. You ask me in game? I'll definitely tell you.

Or hell, PM Matrik on QHCF.net and I'll tell you.