There are two types of collections - Cosmetics and Hero Masters.

Cosmetics
Complete collections of cosmetics to earn stat buffs for your heroes! For each cosmetic collection you complete, earn points to increase your collection levels. You can collect emojis, avatars, and avatar borders through events, contests, and the cosmetics crate.

Hero Mastery
Master heroes in collections to earn rewards, permanent stat buffs, and Mastery Tokens!

Heroes are grouped into collections based on something they have in common, such as combat role, mechanics, theme, or the same Disney/Pixar movie. You can master heroes and complete collection levels by winning battles using those heroes in Creep Surge, City Watch, and Invasion Breaker Battles. Each Collection has 4 tiers to master!

The following do not count toward Mastery:
* Raids
* Mercenaries
* Invasion Ward Battles
* Invasion Boss Battles

Spend Mastery Tokens to purchase special avatar badges and borders from the shop. Unlock tier 1 badges and borders to unlock tier 2 versions!