Marian Slingeneyer vs Haruyama Koichi: who would win?

Haruyama Koichi favored — Slight edge (~55%)

Marian Slingeneyer · Toaru Majutsu no Index · Base

Tier

9-C, up to HIGH 1-C

Attack Potency

Street Level, up to High Complex Multiverse Level

Speed

Average Human, up to Supersonic

Durability

Street Level

Haruyama Koichi · Crows x Worst · Base

Tier

9-C, up to 9-B

Attack Potency

Street Level, up to Wall Level

Speed

Subsonic

Durability

Street Level, up to Wall Level

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