Megatron (Dreamwave Unicron Trilogy) vs Rip Tristan: who would win?

Rip Tristan favored — Slight edge (~55%)

Megatron (Dreamwave Unicron Trilogy) · Transformers · Megatron (Energon)

Tier
HIGH 7-A
Attack Potency
Large Mountain Level
Speed
Superhuman, up to Massively Hypersonic+
Durability
Large Mountain Level

Rip Tristan · Undead Unluck · End of Autumn Arc - Ragnarök Arc

Tier
HIGH 7-A
Attack Potency
Large Mountain Level
Speed
High Hypersonic
Durability
Large Mountain Level

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