Small question

AGSY6

How do I and for what do I use a mastery serum for?

Furrymoosen

If you look in the masteries you will see there are 6 different masteries with class symbols on them. Each class has a mastery that benefits only their class. The serums are used to unlock progressing levels of those masteries.

SummonerNR

But I wouldn’t necessarily put Mastery Points into any of the 6 Class-Based masteries (maybe the Mystic one, but someone new shouldn’t even be bothering with that one for a while).

However, the non-class Mastery Cores (cheaper Stoney Cores, and more expensive Carbo Cores) are used to UNLOCK various much more important Mastery Nodes (as well as for some, each next Level within that Mastery Node too).

https://forums.playcontestofchampions.com/en/discussion/365789/mastery-loadout-guides#latest

BloodyRose

There's a lot of articles on how masteries work. Start here https://help.kabamsupport.com/hc/en-us/articles/360052205012-Mastery-Guide