| Merciless | Details | Pokémon | 
| Name | Jp. Name | ||
| Merciless | Wicked ひとでなし | ||
| Game's Text: | |||
| The Pokémon's attacks become critical hits if the target is poisoned. | |||
| Blocks Role Play & Doodle | Blocks Receive & Power of Alchemy | Blocks Entrainment | Blocks Trace | 
| No | No | No | No | 
| Blocks Skill Swap & Wandering Spirit | Blocks Gastro Acid & Neutralizing Gas | Removed by Mold Breaker / Turboblaze / Teravolt | Not used if user is Transformed | 
| No | No | No | No | 
Pokémon that can have the Merciless ability:
| No. | Pic | Name | Type | Abilities | Base Stats | ||||||
| HP | Att | Def | S.Att | S.Def | Spd | ||||||
| #0747 | 
 | Mareanie |     | Merciless Limber | 50 | 53 | 62 | 43 | 52 | 45 | |
| #0748 | 
 | Toxapex |     | Merciless Limber | 50 | 63 | 152 | 53 | 142 | 35 | |
Pokémon that can have the Merciless ability as their Hidden Ability:
| No. | Pic | Name | Type | Abilities | Base Stats | |||||
| HP | Att | Def | S.Att | S.Def | Spd | |||||


