No. Diancie has no evolutions, though it can Mega Evolve in some games.

What type is Diancie?

Diancie is a dual Rock/Fairy type Pokémon.

What is Diancie weak to?

Diancie is Rock/Fairy. It takes 4× from Steel and 2× from Water, Grass and Ground.

No. 0719 · Gen 6

Impish: Raises its best defense and drops Sp. Atk, which it won't use.

Hit DIANCIE with Steel for 4× damage. Water, Grass and Ground also deal 2×.

4×Hits hardest

2×Super effective

½×Not very effective

0×No effect

In Pokémon GO: Steel deals 2.56× instead of 4×. GO chart

ImpishRaises its best defense and drops Sp. Atk, which it won't use.

Worked out from base stats. Your team may need something else.

Defeating Diancie gives 1 Defense EV, 2 Sp. Def EVs.

The strongest attacking move it can learn in each type, across all games. Not every game has every move. Same-type moves get a 1.5× bonus.

Type	Move	Kind	Power
Normal	Explosion	Physical	250
Rock	Meteor Beamsame type	Special	120
Fairy	Misty Explosionsame type	Special	100
Psychic	Psychic	Special	90
Ground	Earth Power	Special	90
Steel	Flash Cannon	Special	80
Fighting	Body Press	Physical	80
Fire	Mystical Fire	Special	75

Regular Pokémon whose same-type moves hit it hard and who take little from its same-type moves. Picked from types and base stats only, not movesets.