Rei'sen vs Coco Adel: who would win?

Rei'sen favored — Slight edge (~55%)

Rei'sen · Touhou Project · Base

Tier

8-B, up to HIGH 6-A

Attack Potency

City Block Level+, up to Multi-Continent Level

Speed

Infinite

Durability

City Block Level+, up to Multi-Continent Level

Coco Adel · RWBY · Post-Haven

Tier

8-A

Attack Potency

Multi-City Block Level

Speed

Relativistic

Durability

Multi-City Block Level

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