Charlie Morningstar vs Rain (Federation of Martial Arts): who would win?

Rain (Federation of Martial Arts) favored — Slight edge (~55%)

Charlie Morningstar · Hazbin Hotel · Base

Tier
9-C, up to 5-B
Attack Potency
Street Level, up to Planet Level+
Speed
Subsonic+, up to Supersonic
Durability
Street Level, up to Planet Level+

Rain (Federation of Martial Arts) · Mortal Kombat · Base

Tier
9-C
Attack Potency
Street Level
Speed
Massively Hypersonic+
Durability
Street Level

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