Princess Luna vs Cyrus: who would win?

Princess Luna favored — Slight edge (~55%)

Princess Luna · My Little Pony · Princess Luna/Nightmare Moon

Tier

2-A, up to LOW 1-C

Attack Potency

Multiverse Level+, up to Low Complex Multiverse Level

Speed

Infinite

Durability

Multiverse Level+, up to Low Complex Multiverse Level

Cyrus · Pokémon · Pokémon Team (Gen 7)

Tier

LOW 1-C

Attack Potency

Wall Level+, up to Low Complex Multiverse Level

Speed

Relativistic+, up to Infinite

Durability

Low Complex Multiverse Level

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.