I'm the first person to reach A Rank. My dark horses were Decidueye and Rhypherior. It took a really long time. Here is my proof below.
Here is the team I used to make it there:
https://pokepast.es/c2abf4078b582e70
After using both my dark horses for 3 weeks, this is what I have to say about them.
Decidueye probably deserves its position as C+ rank on the viability rankings. It doesn't do that much against more offensive builds due to its poor defenses and speed, but if you can get it in for free, it can usually kill something with sinister arrow raid. It is best against more defensive builds, but it still requires a lot of support, a lot more than other stall breakers in my opinion. It is very weak to toxic/scald burns, making it risky for decidueye to come in on all the bulky waters and ground types that it would want to set up on. If you are not running roost (I ran substitute most of the time to prevent being pursuit trapped) it can get worn down very easily against stall before it has the chance to break through. To be honest, it is kind of a worse version of the nasty plot celebi set. It was still very fun to use.
Rhypherior worked just like it thought it would for the most part. It reliably was able to check birds, could pretty much sponge any non grass/water type hit and either set up rocks or hit really hard thanks to its great attack and stabs. Unfortunately a lot of electric types run grass moves these days, but even with that rhypherior definitely deserves a spot on a lot more teams as it was very reliable and capable at what it does. Running avalanche/megahorn was also fun as it destroyed all the dragons that mindless thought they could drop a draco.
After this successful Dark Horse run, I might decide to do another one next month with noivern or something. Thanks for all the support.
