How to Get Gallade in Pokémon X and Y

Catch a Ralts. They are a very rare find in Route 4. If you want a Gallade, though, you will absolutely need to have the Ralts be a male.

Weaken down the Ralts. The middle to low yellow HP should do it. Do not faint it, as it is a very rare find.

Evolve him into Kirlia. Ralts evolves at Level 20. If you want some moves Gallade cannot learn, mainly Hypnosis, wait for as long as you want before evolving him.

Get HM04 Surf. This is required to evolve Kirlia into Gallade, meaning you cannot evolve your Gallade before you defeat the 3rd gym leader.

Find a Dawn Stone. A Dawn Stone can be found in Route 3 by surfing.

Use the Dawn Stone on Kirlia.

Enjoy using a Gallade!