Marluxia vs Ruminas Valentine (Light Novel): who would win?

Too close to call

Marluxia · Kingdom Hearts · Kingdom Hearts III

Tier

1-C

Attack Potency

Complex Multiverse Level

Speed

Infinite

Durability

Multiverse Level, up to Complex Multiverse Level

Ruminas Valentine (Light Novel) · Tensei Shitara Slime Datta Ken · With Ultimate Skill

Tier

1-C

Attack Potency

Complex Multiverse Level

Speed

Relativistic+, up to Speed Of Light

Durability

Low Complex Multiverse Level

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