Dark does ×1 to Fire

Generations VI to IX, single types. The other way round, Fire against Dark, is ×1.

69 Dark and 81 Fire species among the 1025 this site covers.

Attacker, Dragon and Dark Roaring Moon sprite

damage×1Generations VI to IX

Defender, Fire and Flying Ho-Oh sprite

Ho-Oh #0250

Dark did not exist in Generation I, so Dark against Fire has no value there.

Strongest Dark attackers

Roaring Moon leads Dark at Atk 139

Sturdiest Fire defenders

Dual types that change the answer