Zappa vs Kumara: who would win?

Zappa favored — Slight edge (~55%)

Zappa · Guilty Gear · Pre-Xrd

Tier

6-A

Attack Potency

Continent Level

Speed

Relativistic+

Durability

Continent Level

Kumara · Tensei Shitara Slime Datta Ken · Awakened Demon Lord

Tier

6-A, up to 3-A

Attack Potency

Continent Level, up to Universe Level

Speed

Massively Hypersonic, up to Massively Ftl

Durability

Continent Level, up to Universe Level

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