Champions and enemies alike have affinity and each have its own strength and weakness versus the other affinity. The four affinity are as follows:
Magic (Blue): Beats Spirit (Green), weak to Force (Red);
Spirit (Green): Beats Force (Red), weak to Magic (Blue);
Force (Red): Beats Magic (Blue), weak to Spirit (Green);
Void (Purple): No counter, no weakness.
When attacking the same affinity type (magic vs magic) there are no buffs / debuffs unlike when attacking different affinity (magic vs spirit) which the magic gets an advantage over spirit.
Strength:
+15% Critical rate
+30% Strong hit chance
+30% Damage when a strong hit occurs.
Weakness:
-20% Damage
+35% Weak hit chance
A chance of a Skill landing as a Critical Hit is reduced by 15%
When a weak hit occurs -30% Damage, debuffs cannot be applied