Litten is gonna be a Fire, Ground type.

Popplio is gonna be a Water, Fighting type.

Rowlet is gonna be flying, grass type.

Look at the types of the XY starters.

It goes like this.

Delphox > Greninja > Chesnaught.

Water is weak to grass. Dark is weak to fighting.

Making water, dark be countered perfectly by a grass fighting type.

Just watch the video!! •U•