Slan vs Kikoru Shinomiya: who would win?

Slan favored — Slight edge (~55%)

Slan · Berserk · Base

Tier

7-A, up to 6-C

Attack Potency

Mountain Level+, up to Island Level

Speed

Massively Hypersonic+

Durability

Mountain Level+

Kikoru Shinomiya · Kaiju No. 8 · Numbers Weapon Suit

Tier

7-A, up to HIGH 6-A

Attack Potency

Mountain Level+, up to Multi-Continent Level

Speed

High Hypersonic, up to Ftl

Durability

Mountain Level+, up to Multi-Continent Level

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