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The higher you get in level, the lower a monster's XP that is rendered to you.

Completely true. If you kill a weak creature at the end of the game, you'll not get any XP points.

I have also noticed that some quests give more XP points if you solve them later in the game.

If you want to get a lot of XP points : kill a lot of strong creatures since the beginning of the game and solve the easy quests later.

For exemple : the quest Graham vs Cirgon in Verdistis.
At the beginning of the game, you will get more XP by killing Cirgon.
At the end of the game, you will get more XP by not killing Cirgon.

Barta

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