Ken Kaneki vs ZERO-ONE: who would win?

ZERO-ONE favored — Slight edge (~55%)

Ken Kaneki · Tokyo Ghoul · Post-Rose Arc

Tier
7-C, up to HIGH 7-C
Attack Potency
Large Town Level, up to Town Level+
Speed
Massively Hypersonic+, up to Sub-Relativistic
Durability
Large Town Level, up to Town Level+

ZERO-ONE · Pokémon · Normal

Tier
7-C
Attack Potency
Town Level
Speed
Massively Hypersonic
Durability
Mountain Level+

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