Tank
Frontline and damage absorption are needed.
37.5%
Core
Alternatives
Runes
Resolve + Precision, keystone Aftershock.
Spells
Flash + Smite
Skill order
W > Q > E > Q > Q > R > Q > E > Q > E > R > E > E

Champion build
Ranked build for Rammus: core items, alternatives, runes, spells and skill order from analyzed matches.
Frontline and damage absorption are needed.
Resolve + Precision, keystone Aftershock.
Flash + Smite
W > Q > E > Q > Q > R > Q > E > Q > E > R > E > E