Originally posted by JPValheim:

After that, the game looks at the player and what monsters they have killed to determine what event they can trigger.

For example, a newbie can play on a server with all bosses turned in. The newbie will not trigger any hard events because they are not eligible to trigger them. However, if a veteran player is also around; then the veteran player can trigger the hard events, even if the newbie is there.

I've noticed this while playing on my dedicated server; my novice characters only trigger the forest is moving event; while my other characters can trigger much more intense events. So, it is not only the state of the server; but also the state of each character.

The keys are not stored on the character, they are stored on the world. The world doesn't care if a character has killed something, it only cares if something has been killed on it.