Giratina is as close as a counter you get for Extremekiller. Also if Arceus drops Life Orb for Silk Scarf, +2 Shadow Claw doesn't 2HKO Giratina usually.
Missing Will-O-Wisp sucks but at least you can Dragon Tail it out if you don't want to risk that 25%. Roar works to temporary stop it. Scarf Terrakion doesn't even OHKO Arceus. Non Toxic Skarmory loses if Arceus has Recover or fire-type attack, rare but they still exist.
Missing Will-O-Wisp sucks but at least you can Dragon Tail it out if you don't want to risk that 25%. Roar works to temporary stop it. Scarf Terrakion doesn't even OHKO Arceus. Non Toxic Skarmory loses if Arceus has Recover or fire-type attack, rare but they still exist.