Scorpio Milo vs Arkham: who would win?

Scorpio Milo favored — Slight edge (~55%)

Scorpio Milo · Saint Seiya · Sanctuary Arc

Tier

4-C, up to 4-A

Attack Potency

Star Level, up to Multi-Solar System Level

Speed

Speed Of Light

Durability

Star Level, up to Multi-Solar System Level

Arkham · Devil May Cry · Base

Tier

4-C, up to 4-A

Attack Potency

Star Level, up to Multi-Solar System Level

Speed

Massively Hypersonic+, up to Ftl

Durability

Star Level, up to Multi-Solar System Level

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