Shiki Ryougi (Saber) vs Rad: who would win?

Rad favored — Slight edge (~55%)

Shiki Ryougi (Saber) · Nasuverse · Base

Tier
1-A
Attack Potency
Outerverse Level
Speed
Relativistic+, up to Immeasurable
Durability
Large Island Level

Rad · Dungeons & Dragons · Old One

Tier
1-A
Attack Potency
Outerverse Level
Speed
Ftl, up to Immeasurable
Durability
Outerverse Level

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