Gelda vs Tahu: who would win?

Gelda favored — Slight edge (~55%)

Gelda · Nanatsu no Taizai · Base

Tier

HIGH 7-A, up to 6-C

Attack Potency

Large Mountain Level, up to Island Level

Speed

Sub-Relativistic+

Durability

Solar System Level

Tahu · Bionicle · Post-Golden Armor

Tier

6-C, up to HIGH 5-A

Attack Potency

Island Level, up to Brown Dwarf Level

Speed

Massively Hypersonic+, up to Relativistic

Durability

Island Level

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