Double Spot battle Help me plz

[ddxthekid]

Hi, im pretty new to double spot battling im currently building my first real team and short on the last spot.
So here is my question.
What role should my last pokemon fill?
What pokemon could fill that role??(i like originality over top overplayed we see in evry VGC battles)

here is my present list

Alteria(mega stone)
-adamant nature
-ability natural cure
earthquake
return
dragon dance
roost

Aerodactyl(focus sash)
-jolly nature
Ability unerve
Rock slide
sky drop
wide guard
protect

Tornadus(life orb)
-timid nature
Ability Prankster
Aerial slash
focus blast
taunt
Protect

Clefairy(eviolite)
-Bold nature
Ability Friend guard
MoonBlast
follow me
thunder wave
Protect

Arcanine(sitrus berry)
-Bold nature
Ability intimidate
flamethrower
will-o-wisp
helping hand
Protect