91/90/129/90/72/108
As the leader of the three musketeers Cobalion provided a thoroughly dissapointing performance in OU where it was overshadowed by its two brothers. Entering UU, Cobalion redemms itslef, becoming a firmly entrenched threat to many teams.
At first glance one notices Cobalion's excellent 108 base speed, allowing it to outpace most of the unScarfed tier, quite useful as many of its sets carry Taunt to stop stall pokemon. While its average 90 base offenses and paltry base 72 Special Defense may seem like weak points at first, Cobalion has ways to remove both of those problems in the form of Swords Dance and Calm Mind. With these moves, in conjunction with Taunt Cobalion is able to safely boost its chosen attack stat while avoiding potentially crippling status.
The Swords Dance set is the most common set run by Cobalion as it is able to set up quicker and defeat stall teams easier. Cobalion is able to easily set up on pokemon like Deoxys-D, Chansey and Mew, although in Mew's case it must be wary of Aura Sphere. The set provides excellent coverage between Close Combat and Stone Edge, forgoing Iron Head due to its redundant coverage with Close Combat. While this set is effective there are a couple of pokemon that do beat it. Both Nidoqueen and Nidoking resist its main attacking option, KOing in return with Earth Power, while the omni-present physical wall, Slowbro can comfortably take a Stone Edge, heal any damage and attack with one of its three main attacking moves. The main dilemma on Cobalion is the choice between LO and Leftovers. If one choose Life Orb the are vulnerable to being worn down by smart switching and being killed by something like Raikou, but if you dont you miss a kill on Wobbufett at +6.
The Calm Mind set is a much slower pokemon to set up but still effective. This set abuses its STAB options in Focus Blast and Flash Cannon with the last slot going to a selected hidden power type or Taunt. With Cobalions lack of recovery it can usually only get 2 or 3 boosts but is still useful in getting by usual Cobalion checks such as Slowbro and fast speacial attackers, although Chansey will now be able to wall you. In addition, one can choose to run Sacred Sword. As Sacred Sword is a special move, its power gets boosted by Calm Mind, however, Sacred Sword hits the opponent for physical damage, meaning that things like Chansey and Calm Mind Suicune no longer wall you.
With its immunity to poison type status Cobalion is also capable of running a support set. Having a plethora of resistances and access to Thunder Wave and Taunt, Cobalion will find many occasions stop a set-up and spread status. However this set suffers from a distinct lack of power. As Iron Head is the STAB of choice, due to Close Combat's side effect negating the purpose of this set, Cobalion suffers from both coverage issues and an unboosted Iron Head coming off of an unboosted 90 base attack stat.
Despite Cobalion's shortcomings, it is an excellent member of the UU tier capable of causing huge damage to opposing team members.