I think Klefki should be a A+, and not S-. I don't really get what Greninja can do, other than Toxic Spikes, but I think it should be D Rank.
I forward Ho-Oh for S-, too. (Although I don't understand how it's a Darkrai check. +2 252 SpA Darkrai Dark Pulse vs. 248 HP / 52 SpD Ho-Oh: 178-210 (42.8 - 50.6%) -- 2% chance to 2HKO means that Stealth Rock = dead. If you screw up on predicting your opponent or Sleep Talk RNG fails you, you also lose. If the opponent doesn't run Nasty Plot, it probably will run Taunt or Sludge Bomb. It can deal with Sludge Bomb, but to beat Taunt, Ho-oh would have to switch in and out for recovery, which could hurt the entire team) Ho-oh is one of the best CM SteelCeus checks (Oh yeah, I think SteelCeus should be promoted to A or A+ rank, as it's one of the best late game sweepers in AG), can beat Xerneas 1on1 (Thunder is a thing, but people can run EVs to survive one at +2), pressure opponents with Life Orb, Lum, Choice Band, Thunder Wave, Toxic, or Substitute. (Personally, I find the Life Orb + T-wave sets to be devastating)
Finally, can Blissey/Chansey/Clefable leave D Rank? Like, C- for beginners, but at least not D rank.
I forward Ho-Oh for S-, too. (Although I don't understand how it's a Darkrai check. +2 252 SpA Darkrai Dark Pulse vs. 248 HP / 52 SpD Ho-Oh: 178-210 (42.8 - 50.6%) -- 2% chance to 2HKO means that Stealth Rock = dead. If you screw up on predicting your opponent or Sleep Talk RNG fails you, you also lose. If the opponent doesn't run Nasty Plot, it probably will run Taunt or Sludge Bomb. It can deal with Sludge Bomb, but to beat Taunt, Ho-oh would have to switch in and out for recovery, which could hurt the entire team) Ho-oh is one of the best CM SteelCeus checks (Oh yeah, I think SteelCeus should be promoted to A or A+ rank, as it's one of the best late game sweepers in AG), can beat Xerneas 1on1 (Thunder is a thing, but people can run EVs to survive one at +2), pressure opponents with Life Orb, Lum, Choice Band, Thunder Wave, Toxic, or Substitute. (Personally, I find the Life Orb + T-wave sets to be devastating)
Finally, can Blissey/Chansey/Clefable leave D Rank? Like, C- for beginners, but at least not D rank.