Kamen Rider Kuuga vs Kazumi: who would win?

Kamen Rider Kuuga favored — Slight edge (~55%)

Kamen Rider Kuuga · Kamen Rider · Amazing Mighty Form

Tier

6-C

Attack Potency

Island Level

Speed

Superhuman, up to Hypersonic

Durability

Island Level

Kazumi · Puella Magi Verse · Real Magical Girl

Tier

6-C, up to 5-C

Attack Potency

City Level, up to Moon Level

Speed

Massively Hypersonic, up to Massively Hypersonic+

Durability

City Level, up to Mountain Level

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