FerrothornGrassSteel

• Speed IV 31 or 0
• 232 Special Defense EVs ensure Ferrothorn survives three Choice Specs Greninja's Dark Pulses from full HP.
• Other viable spreads

ㄴ Impish / Relaxed 252 HP / 88 Def / 168 SpD, Leftovers or Rocky Helmet
ㄴ Impish / Relaxed 240 HP / 252 Def / 16 SpD, Leftovers or Rocky Helmet
From the pvp-ferrothorn tag