Izis vs Pegasus Seiya: who would win?

Izis favored — Slight edge (~55%)

Izis · Tensei Shitara Slime Datta Ken · Base

Tier

2-A

Attack Potency

Multiverse Level+

Speed

Massively Hypersonic+

Durability

Multiverse Level+

Pegasus Seiya · Saint Seiya · Pegasus God Cloth

Tier

2-A, up to LOW 1-C

Attack Potency

Multiverse Level+, up to Low Complex Multiverse Level

Speed

Transonic, up to Infinite

Durability

Multiverse Level+, up to Low Complex Multiverse Level

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