Listing AV Tangrowth as a counter:
Tangrowth @ Assault Vest
Ability: Regenerator
EVs: 252 HP / 144 Def / 112 SpD
Sassy Nature
- Leaf Storm
- Knock Off
- Earthquake
- Hidden Power [Ice]
EVs maximize physical bulk to help against Secret Sword while having some special investment to comfortably take a Water Spout. Regenerator helps Tangrowth shrug off attacks and come in later if the need arises.
252 SpA Choice Specs Keldeo Water Spout (150 BP) vs. 252 HP / 112+ SpD Assault Vest Tangrowth: 159-188 (39.3 - 46.5%) -- guaranteed 3HKO
252 SpA Choice Specs Keldeo Secret Sword vs. 252 HP / 144 Def Tangrowth: 153-180 (37.8 - 44.5%) -- guaranteed 3HKO
And if Keldeo decides to stay in, he eats this:
0 SpA Tangrowth Leaf Storm vs. 0 HP / 4 SpD Keldeo: 330-390 (102.1 - 120.7%) -- guaranteed OHKO
Tangrowth can also handle threats like Diggersby fairly well, tanking a +2 Extreme Speed and then retaliating with a Leaf Storm OHKO.
Tangrowth @ Assault Vest
Ability: Regenerator
EVs: 252 HP / 144 Def / 112 SpD
Sassy Nature
- Leaf Storm
- Knock Off
- Earthquake
- Hidden Power [Ice]
EVs maximize physical bulk to help against Secret Sword while having some special investment to comfortably take a Water Spout. Regenerator helps Tangrowth shrug off attacks and come in later if the need arises.
252 SpA Choice Specs Keldeo Water Spout (150 BP) vs. 252 HP / 112+ SpD Assault Vest Tangrowth: 159-188 (39.3 - 46.5%) -- guaranteed 3HKO
252 SpA Choice Specs Keldeo Secret Sword vs. 252 HP / 144 Def Tangrowth: 153-180 (37.8 - 44.5%) -- guaranteed 3HKO
And if Keldeo decides to stay in, he eats this:
0 SpA Tangrowth Leaf Storm vs. 0 HP / 4 SpD Keldeo: 330-390 (102.1 - 120.7%) -- guaranteed OHKO
Tangrowth can also handle threats like Diggersby fairly well, tanking a +2 Extreme Speed and then retaliating with a Leaf Storm OHKO.