User:Chris/dNetHack/Anachrononaut Astral Plane
Once you arrive on the Astral Plane, there are two things you have to do:
1. Use the Annulus to annul Ilsensine's high altar, thus saving the future.
2. Offer the Amulet of Yendor to your own god's high altar, thus ascending as usual.
You can ascend normally without saving the future, or save the future (and then die), but to achieve a full scoring ascension you must save the future before ascending. This would require seeking out Ilsensine's high altar, dealing with its two attendants and then invoking the Annulus in its silver chakram form while standing on top of the high altar, thus ejecting Ilsensine from this universe. Note that this will destroy the Annulus, so bring some backup weapons! Once you are done, you can seek out the coaligned high altar and win the game.