City of a Thousand Towers
Marselene's thoughts on her ascension
Marselene feels the gods have not smiled on her as they have on the rest of you because she has not participated fully in your adventures, mostly hanging back to aid you but not to defeat your foes.
If she could get the killing blow on one of your greater foes, that might do the trick, although she is not much of a warrior and is rather uncertain of her longevity should she attempt that, especially given your more recent adversaries.
Perhaps it might be sufficient and more survivable to help desecrate the Pulchra Umbra temple’s altar. This altar is actually the pool of Ioqua that the Pulchra Temple Guardian normally resides in. This pool is an artificial construct in the Scar. She thinks you might be able to desecrate the pool by damaging the stonework of it to cause to drain into the fissures that run beneath it.
Another option might be if she can redeem Ventrix somehow and turn her back to the light.