Kamen Rider Build vs Beyonder: who would win?

Beyonder favored — Slight edge (~55%)

Kamen Rider Build · Kamen Rider · The Real World

Tier

HIGH 1-A

Attack Potency

High Outerverse Level

Speed

Average Human, up to Immeasurable

Durability

High Outerverse Level

Beyonder · Marvel · Escaped from the House of Ideas

Tier

HIGH 1-A

Attack Potency

High Outerverse Level

Speed

Infinite, up to Omnipresent

Durability

High Outerverse Level

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