Here we go! This is what I've been talking about: Keldeo is similar to Kyurem-B in that simply having a "check" is not good enough. Just as you can't sponge Outrages without a physically defensive Steel-type, Keldeo cannot and will not be walled without serious, resisted bulk, or immunity. Keldeo's rain-boosted Hydro Pumps are the most powerful attack in OU, and unlike Darmanitan or Victini (whose STABs are more powerful in neutral weather [In fact, I believe that Darmanitan's Flare Blitz is the second or third most powerful attack in the history of Pokémon]) Keldeo has the typing and stat spread to be one of the premier threats of OU. I kinda felt like I got off track on the part about checks and counters, so lemme reiterate: Keldeo is not like Terrakion where you can say "Well, I don't have room for Gliscor, but I do already have Choice Band Scizor, so he can check Terrakion." If you don't allot room specifically, very specifically, to account for Keldeo, you're gonna have a bad time.