I love going against Aegislash if the team I'm using has a Bisharp. If I think I can outpredict it, I can set up SD while it King Shield's and sweep. Even if I hit it with Knock Off during its King's Shield, Bisharp's Defiant ability boosts his Attack right back up so there's no risk fighting it. IIRC Dread Plate Knock Off is a guaranteed KO on 252 HP / 0 Def which is what most Aegis run.

You want the hardest check to Aegislash in the game? Bisharp.

ty based bisharp