The rules for using Overlord cards state that they go to a "discard" pile after use. But on the activation card side labelled "Overlord Turn Summary", under start of turn it states to III. Refresh cards. I haven't yet discovered any overlord cards that specify to "exhaust" them, so I'm not clear what it means to "Refresh" cards (if none are actually "exhausted"). Once an overlord card enters the "discard" pile, does it get "refreshed" prior to the next overlord turn, or does it remain in the discard pile until the end of the encounter?
Put another way, how many times per encounter does an overlord card get used? Once, or on every single overlord turn? Sorry for the dumb question but thanks in advance for any help on clarifying this!