Rimuru Tempest (Web Novel) vs Darren the Ancient Sleeper: who would win?

Rimuru Tempest (Web Novel) favored — Slight edge (~55%)

Rimuru Tempest (Web Novel) · Tensei Shitara Slime Datta Ken · End of Series

Tier

LOW 2-C

Attack Potency

Universe Level+

Speed

Ftl, up to Infinite

Durability

Universe Level+

Darren the Ancient Sleeper · Adventure Time · Base

Tier

LOW 2-C, up to 2-A

Attack Potency

Universe Level+, up to Multiverse Level+

Speed

Massively Hypersonic+

Durability

Universe Level+, up to Multiverse Level+

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