I really think Noivern can work well with Mega Aggron to make a pretty decent offensive core. Noivern resists or is immune to Mega Aggron's fire, fighting and ground weaknesses while Mega Aggron resists Noivern's ice, dragon, rock and fairy weaknesses. I think this can work well as Noivern is a strong special attacker while Mega Aggron is a strong physical attacker. Mega Aggron can check/counter the following UU pokemon with Iron Head, Earthquake and Stone Edge coverage: Arcanine, Weavile, Tentacruel, Metagross, Mega Manectric, Jirachi, Heracross, Mega Heracross, Gardevoir, Galvantula, Florges, Noivern and Cloyster. Noivern can check/counter the following pokemon with Draco Meteor, Hurricane, Flamethrower, and Focus Blast coverage: Absol, Mega Aggron, Celebi, Forretress, Kangaskhan, Kingdra, Medicham, Trevenant, and Umbreon (I didn't name a pokemon more than once). One problem I see is that they have no good way to deal with bulky waters. Aggron can learn ThunderPunch, but that still leaves no true way to deal with Gastrodon, Donphan, or Sableye. A duo like this could fare well with a grass type teammate to get as much coverage as possible, but I'm still not sure who could fill that spot. Any ideas?