Togekiss is a nice counter for the leader of the muskateers. Thunder wave and serene air slash makes it troubled. also aura sphere too if cobalion is on the special side
Togekiss must beware of a very-likely-to-be-on-the-Moveset Stone Edge and the possibility of Volt Switch. Togekiss is slower than Cobal', so you'll likely get a TWave in only if Cobal' is either switching in to counter Togekiss or spending a turn to buff. Counters only work if they can actually take the hit, which is less than likely with Togekiss since Cobal' won't waste a turn to buff against it due to TWave + Serene Grace-boosted Air Slash Flinching. Cobal' is either going right for the throat with Stone Edge/Volt Switch or switching to a Ground Type or something with Volt Absorb/Motor Drive/Lightningrod to punishing you for your lack of foresight...