Quest chains
A quest with prerequisites stays locked until the player has completed every quest in the list. That is all a chain is.
id: apprentice
name: "<gray>Apprentice"
objectives:
- type: KILL
entity: ZOMBIE
amount: 5
id: journeyman
name: "<yellow>Journeyman"
prerequisites:
- apprentice
objectives:
- type: KILL
entity: SKELETON
amount: 10
id: master
name: "<gold>Master"
prerequisites:
- journeyman
- side_quest_1
objectives:
- type: KILL
entity: WITHER_SKELETON
amount: 3
master needs both journeyman and side_quest_1. Branches work the same way: two paths that end in one quest listing both as prerequisites.
When a player finishes the last prerequisite, the next quest shows up in their /quest log as available. Trying to start a locked quest tells them the prerequisites are not done yet.