Millennian Io vs Power: who would win?

Power favored — Slight edge (~55%)

Millennian Io · Godzilla · Unstable State/Orga

Tier

8-A

Attack Potency

Multi-City Block Level

Speed

Subsonic, up to Supersonic+

Durability

Multi-City Block Level

Power · Chainsaw Man · Blood Devil

Tier

8-B, up to 8-A

Attack Potency

Multi-City Block Level+

Speed

Massively Hypersonic+

Durability

City Block Level+

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