People have already discovered counters for Keldeo in the DW metagame. Bulky Toxicroak in the rain hard counters any Keldeo that doesn't run HP Psychic, Flying, or Ground. Jellicent, Tentacruel, and Latias can also take its attacks but can't do much back after a Calm Mind or two. I don't think Keldeo is going to shake up the metagame as much as you think.
Interesting to see this pony getting so much attention...and disappointing to see so much theorymoning rather than people actually playing DW.
Anyway, it will be rather interesting to see how Keldeo will initially play in standard since I'm fairly sure not a lot of standard players know his "counters". The quick list would be:
Dragonite
Salamence
Slowbro
Slowking
Jellicent
Celebi
Gyarados
Starmie
Latios
Latias
Toxicroak
Amoongus (Only good in DW)
Alakazam
Serperior (DW)
Tornadus
Whimsicott
Venusaur
Tangrowth
Jolteon
Ditto (DW)
And that's of course without diving into the plethora of Choice Scarf Pokemon that can take him down like Terrakion who doesn't mind revenge-killing his little brother.
But as you can see, there is no correct choice of Hidden Power for Keldeo since he needs more than one type to cover all those weaknesses.
HP Ghost sets gets stopped by Dragonite, Salamence, Gyarados, Amoongus, Venusaur, & Serperior.
HP Ice means Jellicent, Gyarados, Starmie, & the Slow-Bros get the best of him.
HP Electric leaves him open to Celebi, Latios, Latias, and ...well everything HP Ghost does minus Gyarados.
Roar?Latias can also take its attacks but can't do much back after a Calm Mind or two.
Dragonite
Salamence
Slowbro
Slowking
Jellicent
Celebi
Gyarados
Starmie
Latios
Latias
Toxicroak
Amoongus (Only good in DW)
Alakazam
Serperior (DW)
Tornadus
Whimsicott
Venusaur
Tangrowth
Jolteon
Ditto (DW)
And that's of course without diving into the plethora of Choice Scarf Pokemon that can take him down like Terrakion who doesn't mind revenge-killing his little brother.
when this keldeo is released, im assuming that since it is an event mon, only the event version will be allowed use in the OU metagame, and so whatever nature it gets will be the nature one has to use much in the same vein as aura sphere raikou?
If that is the case it will probably lose out on its great 108 speed tier, and maybe even have a -spattack nature, so it wont be too gamebreaking
I think that keldeo is going to experience more than "reasonable success," personally.
The thing is, Keldeo is undoubtedly going to have a gigantic impact on the metagame. All of its primary checks are offensive, bar Jellicent who eats a super effective Hidden Power. Keldeo can afford to run something that's not HP Ice because Hydro Pump is just INSANELY powerful. I'm talking about a 2HKO on offensive Dragonite, through Multiscale. I'll let the implications of that sink in. Personally, the only reliable way to beat this thing is through revenge killing it with powerful physical attackers, ala Scarf Terrakion and possibly things like Raikou in the rain if its not a CM variant.
edit: btw, this is the list of reliable counters for Keldeo:
Slowbro
Slowking
Jellicent
Celebi
Starmie
Latios
Latias
Toxicroak
Amoongus (Only good in DW)
Tornadus
Venusaur
Tangrowth
Ditto (DW)
The pokemon above are really the only things that can switch into Keldeo most of the time, since it's gonna be spamming Hydro Pump more often than not. Everything else on Katakiri's list is handily 2HKOed by specs Hydro Pump.
(btw this is coming from someone who's been playing DW OU for a bit now)
The thing with that is unless you're giving up one of your STAB moves, you're not really doing much of anything to it back.... CM/ Pump / Taunt / HP Electric might work to get it but that's iffy considering Water coverage isn't that good by itself, though it could catch a player off guard, letting you boost enough where resistances don't matter
CM, taunt, hydro pump, secret sword was what I had in mind.
How about pairing Keldeo with <snip>
The thing is, Keldeo is undoubtedly going to have a gigantic impact on the metagame. All of its primary checks are offensive, bar Jellicent who eats a super effective Hidden Power. Keldeo can afford to run something that's not HP Ice because Hydro Pump is just INSANELY powerful. I'm talking about a 2HKO on offensive Dragonite, through Multiscale. I'll let the implications of that sink in. Personally, the only reliable way to beat this thing is through revenge killing it with powerful physical attackers, ala Scarf Terrakion and possibly things like Raikou in the rain if its not a CM variant.
edit: btw, this is the list of reliable counters for Keldeo:
Slowbro
Slowking
Jellicent
Celebi
Starmie
Latios
Latias
Toxicroak
Amoongus (Only good in DW)
Tornadus
Venusaur
Tangrowth
Ditto (DW)
The pokemon above are really the only things that can switch into Keldeo most of the time, since it's gonna be spamming Hydro Pump more often than not. Everything else on Katakiri's list is handily 2HKOed by specs Hydro Pump.
(btw this is coming from someone who's been playing DW OU for a bit now)
Does tentacruel do a good job at countering keldeo?? It has excellent special defense, so it can probably take a hit or two.
Without Toxic it really can't do anything back...