How Does Serene Grace Work?

Serene Grace doubles the chance of secondary effects on moves. Since the move Air Slash has a 30% chance to flinch the target, the ability Serene Grace doubles that chance to a 60% chance to flinch the target.

Does Serene Grace affect metronome?

Although the following moves are affected by the Ability, they currently cannot be learned by any Pokémon with Serene Grace. They may, however, be called via Metronome, Mirror Move, Copycat, or Mimic, or be used by a Pokémon that gained Serene Grace by Trace or a move such as Skill Swap or Role Play.

Does Serene Grace affect critical hits?

In battle. Serene Grace doubles the chance of moves' secondary effects occurring - specifically stat changes, status ailments, or flinching. It also boosts the 10% chance of a King's Rock or a Razor Fang. Serene Grace does not affect the bearer's critical hit ratio, nor the move Secret Power.