quest
Primarily used in role-playing games and fantasy contexts for a mission or task given to a character.
I accepted the next quest.
I accepted a quest from a villager.
このクエストをクリアすると、レアアイテムがもらえる。
If you clear this quest, you can get a rare item.
I finally cleared this quest.
I decided to progress the main quest.
I tried taking on a difficult quest.
subquest; side quest
Borrowed from English 'quest', used in Japanese primarily in gaming and fantasy contexts.