Griffin vs Bjorn: who would win?

Griffin favored — Slight edge (~55%)

Griffin · Doctor Who · Base

Tier
10-B, up to LOW 1-C
Attack Potency
Low Complex Multiverse Level
Speed
Immeasurable
Durability
Human Level

Bjorn · Vinland Saga · Base

Tier
9-C, up to 9-B
Attack Potency
Street Level, up to Wall Level
Speed
Unknown
Durability
Street Level, up to Wall Level

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