Keicho Nijimura vs Hundun: who would win?

Hundun favored — Slight edge (~55%)

Keicho Nijimura · JoJo's Bizarre Adventure · Base

Tier

9-C, up to 9-A

Attack Potency

Street Level, up to Small Building Level

Speed

Below Average Human, up to Relativistic

Durability

Small Building Level

Hundun · Toaru Majutsu no Index · Base

Tier

9-C

Attack Potency

Street Level

Speed

Subsonic

Durability

Small Building Level

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