Kamen Rider Delta vs Katsuya Serizawa: who would win?

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

Kamen Rider Delta · Kamen Rider · Kamen Rider Delta

Tier

7-C

Attack Potency

Town Level+

Speed

Relativistic+, up to Speed Of Light

Durability

Town Level+

Katsuya Serizawa · Mob Psycho 100 · Base

Tier

7-C

Attack Potency

Town Level+

Speed

Massively Hypersonic

Durability

Town Level+, up to Small Country Level

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