Let's get it out of the way right here. We all know that Keldeo looks like a My Little Pony. Under that cutesy guise, however, is an extremely formidable Pokémon that can rip right through you if you're not careful. Let's start with a closer look at Keldeo's stats:
Sp. Attack: 129
Sp. Def: 90
Just looking at base stats, Keldeo doesn't look that spectacular. Sure, it's Sp. Attack is quite high, but it's frail as well. But hold your effeminate horse warriors, folks. What you can't overlook about Keldeo is its movepool, specifically Secret Sword, Hydro Pump, and Calm Mind.
Secret Sword, not to be confused with its sister-move Sacred Sword, is an 85 base-power Fighting-type move that calculates damage using the user's Sp. Attack and the opponent's defense, similar to other moves like Psychoshock or Psystrike. With only Keldeo's most useful STAB moves, Hydro Pump and Secret Sword, you've already got yourself quite the arsenal with almost unresisted coverage. Secret Sword gives Keldeo the ability to act like a mixed sweeper while also not having to forgo Speed or offensive EVs in order to balance out Attack and Sp. Attack.
But, add Calm Mind in, and all of a sudden you're going to regret the not-so-savory things you said about Keldeo and its striking resemblence to Fluttershy and the like. With one Calm Mind boost, a Keldeo doesn't even blink at what would normally be threats to a special sweeper. Blissey? OHKO'd by Secret Sword. Gastrodon? Dispatched with ease. The only real counter that comes to mind is Jellicent, but Keldeo can easily use Hidden Power Ghost as its fourth move to take out Ghost and Psychic types with ease.
Certainly, Keldeo isn't perfect. A well-placed Thunderpunch will teach it who's boss, but that doesn't mean you shouldn't watch out when your opponent brings one to your next match. Keldeo is more than meets the eye, and I don't care if that's the Transformers catchphrase and that it has no relation to My Little Pony.
That'll be it for the week. Leave a comment with your thoughts about Keldeo or your suggestions on what I should cover next time! See ya, Pokéfolk.