Fast class mastery farming: Pair Haze Badge with weak swords or bows against high DefenseMinor spoilers
Use guaranteed damage on a hit to sustain repeated combat, bring enough healing, and pass the badge to the next unit after mastering a class.
Original video: Easy to miss: Highly efficient class EXP and mastery farming | Bilibili creator Pser_hanser.
For mid- and late-game class mastery, equip 
Haze Badge with a low-Attack sword or bow and repeatedly fight high-Defense enemies. The demonstration takes roughly two or three battles per class, provided you have the badge and enough healing.
Obtain the Haze Badge in Part 1
Haze Badge comes from “A Lost Object.” Obtain the reward in Part 1 and use it for mastery farming in Part 3.
This reward appears late in a quest chain. Keep accepting follow-up quests after completing the first one.
Sword and bow hits deal at least five damage
Haze Badge ensures at least 5 damage after a successful hit with a sword or bow equipped.
Check whether the current class can use swords or bows first. If neither is available, this method does not fit. Eligible classes can deliberately use weak weapons against high-Defense enemies for extended combat. Enemies stay alive while minimum damage keeps class experience accumulating. In one demonstrated battle, 
Cai gained nearly 40% progress, completing a class in two or three battles.
Farm slowly against high Defense with healing
- 1Find high-Defense shield enemies on the Part 3 map.
- 2Equip and train.GiveHaze Badge to a unit able to use swords or bows, equip a low-Attack sword or bow, and keep fighting in place.
- 3Bring a healer with enough recovery to cover each round's damage.
- 4Once mastery is full, remove the badge and pass it to the next unit.
Bring a healer with enough output, such as 
Tialla or 
Sofia. Farming takes many rounds. Surviving the first is not enough; later HP losses need healing too.
Rotate the badge between trainees rather than leaving it on someone already finished.
