Killer Instinct
464 Achievements
4,935
354-432h
PC
Arbiter Novice
You have reached 30 fight Challenges with Arbiter!
20
0.87%
How to unlock the Arbiter Novice achievement in Killer Instinct - Definitive Guide
DLC characters can appear in free rotation from time to time. Messing around with them in survival, against a friend, or with bots will naturally unlock most character based achievements. It would take about 10-15min just button mashing, a little bit less if you actually know the characters.
See "Arbiter Master".