Kamen Rider Demons vs Veldora Tempest (Light Novel): who would win?

Kamen Rider Demons favored — Slight edge (~55%)

Kamen Rider Demons · Kamen Rider · End of Series

Tier

1-C

Attack Potency

Complex Multiverse Level

Speed

Massively Ftl+

Durability

Complex Multiverse Level

Veldora Tempest (Light Novel) · Tensei Shitara Slime Datta Ken · Base

Tier

1-C

Attack Potency

Complex Multiverse Level

Speed

Relativistic+, up to Omnipresent

Durability

Complex Multiverse Level

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