Plant Monsters vs Merciless Watchers and Chieftain: who would win?

Merciless Watchers and Chieftain favored — Slight edge (~55%)

Plant Monsters · Godzilla · Base

Tier

8-A

Attack Potency

Multi-City Block Level+

Speed

Immobile, up to Supersonic+

Durability

Multi-City Block Level+

Merciless Watchers and Chieftain · Bloodborne · Base

Tier

8-A

Attack Potency

Multi-City Block Level

Speed

High Hypersonic

Durability

Multi-City Block Level

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