Yeah, no worries. So the Random Encounters section lists which cards become blank on defeat. King, Queen, Jack, and Nine can all become blank. Turning blank is explicitly stated in the rule for each territory when it happens (except queens). All other cards retain their effects. Also, you have to defeat those cards (or activate them in the case of Queen and Jack) as they can be flipped remotely by map, oracle, or mountain climbing and in the case of Jacks, there are special rules per wonder. For instance, the Garden of Plenty only goes blank when the party rolls a one or two on a spoil check, and the vault only when it has been opened with the vault key and looted. The oracle never goes blank, nor does the Twisting Pyramid.
Grinding does require that you move and come back, think of it as restocking the dungeon. You have hunted the beast in its homeland and need to clear the area so they have time to repopulate. The rules for this are in the play procedures; each turn, the party token must be moved, unless prevented by a hard land.
Megabeasts are actually once per game, per beast, as each Megabeast is a different creature with a different Weapon of Legend in its hoard. This allows each of the four players to collect the weapons needed to defeat the end beast. Also, it’s super satisfying to go back to each of the lairs with your specialist (suited character) yolked out with Elven Cloak, maybe a holy rod and a spell book to really add some dice to that encounter and mission impossible the treasure out from under them. Also worth noting here, you cannot kill a Megabeast, they are too large and powerful for that. This is why magic swords and weapons of legend provide no bonus there. The idea is you are robbing their hoard.
