Motherfucker you don't need anything else.
Six Aggron.
First one is your Mega. Make him Careful with Dragon Tail, Rest, Sleep Talk, and Substitute. Put up that sub, and spam Dragon Tail to keep forcing your opponent to switch out. Rest and Sleep Talk when you've taken too much damage.
Your two other Aggron are you setters. Stealth Rock the field; you'll need two in case of shit like Defog and Rapid Spin. This will make your Mega do more damage as he makes your opponent switch. Give them them other support moves too.
Your fourth Aggron is your Fairy fucker. Iron Head, Heavy Slam; anything that will optimize getting rid of Fairies; because those little fags are immune to Dragon Tail.
Fifth Aggron is your potential sweeper, in case everything else goes to Shit. Give him Rock Polish, or if you give one of your setter Aggron Twave to make your opponent slower, Swords Dance. Either way, make him Sturdy with a Weakness Policy. Take a Super Effective attack, survive with Sturdy, then rape bitches with a capitalized Aggron.
Your last Aggron is suitably your last resort. You have no idea how many times this guy has saved my ass. Suppose your opponent has a Mega Lucario. None of your guys can stop that thing. Except this guy. Send him out. Get hit by Aura Sphere. Lose all your health. Sturdy. Metal Burst. OHKO. Your most invaluable member.
