Create a random dungeon system for the endgame.
At some point on the map, place a religious sect that is exploring a magical rift and charging adventurers a fee to enter.
When the adventurer enters the first level of the rift, they have to kill a number of monsters or soldiers to open a door to the next level of the rift. The idea is to always have a boss at the end of each rift, with 3 to infinite levels within the rift.
As a reward for the players, you could include unique items that only drop in these rifts, drinks, and drinks with buffs. Include something that motivates players to continue playing. I know you're creative enough for this.
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