Meditating

Quest leaders and nemeses, Vlad, and the Wizard of Yendor (and perhaps some other unique monsters) are created meditating. They cannot move or attack until you wake them up. Internally, the game splits it into STRAT_WAITFORU and STRAT_CLOSE.

You can wake up your quest leader by #chatting to them. Usually, you will have to become at least fast and move adjacent on a free turn, else they initiate the dialogue themselves, which does not work unless you are ready to get permission.