Grima vs The Joker (Injustice): who would win?

The Joker (Injustice) favored — Favored (~65%)

Grima · Fire Emblem · Echoes

Tier

7-B, up to 4-A

Attack Potency

City Level, up to Multi-Solar System Level

Speed

Superhuman, up to Massively Hypersonic

Durability

Large Island Level, up to Multi-Solar System Level

The Joker (Injustice) · DC · Base

Tier

7-B, up to HIGH 6-A

Attack Potency

City Level, up to Multi-Continent Level

Speed

Massively Ftl+

Durability

Multi-Continent Level

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