While King's Shield + 3 physical attacks Aegislash is viable, it's walled by physical walls like Hippowdon. King's Shield is somewhat easy to play around as well:
-King's Shield
-Shadow Ball
-Shadow Sneak
-Iron Head/Sacred Sword
Nature: Quiet
EVs: 252 HP/4 Atk/252 SAtk
Item: Leftovers
or
-Swords Dance
-Autotomize
-Shadow Claw
-Iron Head/Sacred Sword
Nature: Adamant
EVs: 88 HP/252 Atk/168 Spe
Item: Leftovers
or
-Shadow Ball
-Shadow Sneak
-Iron Head
-Sacred Sword
Nature: Quiet
EVs: 4 HP/252 Atk/252 SAtk
Item: Life Orb/Spooky Plate/Spell Tag
or
-Swords Dance
-King's Shield/Shadow Claw
-Shadow Sneak
-Iron Head/Sacred Sword
Nature: Adamant
EVs: 252 HP/252 Atk/4 Spe
Item: Leftovers
or
-Autotomize
-Shadow Ball
-Hidden Power (Ice)
-Iron Head/Sacred Sword
Nature: Rash
EVs: 88 Atk/252 SAtk/168 Spe
Item: Life Orb/Weakness Policy
If I were to go with the special set for Aegislash, would you suggest I go with flash cannon instead of Iron head or something like that. Based on your suggestions I think that
-King's Shield
-Shadow Ball
-Shadow Sneak
-Flash Cannon
Nature: Brave
EVs: 252 HP, 252 SpA, 4 Att
Item: Leftovers (once again when I can find some, so shell bell will be temporary)
And also good catch on the Sylveon set. I forgot that most resistances are for physical attackers. I'll change that.
And one last question, how in the world am I expected to find all these leftovers when I have no shinies