Obviously this is from the analysis so I will break it down.
(Keep in mind that there may be other possible checks/counters *perhaps* that aren't included)
These are the pokemon listed that can beat...
~CM Arceus-Ghost
-Darkrai (probably our best bet if we're really that concerned about Arceus-Ghost)
-Tyranitar(weather)
-Blissey (loses offensive momentum)
-Chansey (loses offensive momentum)
-Ho-oh (requires a spinner and semi-reliant on weather)
-Kyogre(weather)
~SD Arceus-Ghost
-Darkrai (probably our best bet if we're really that concerned about Arceus-Ghost)
-Tyranitar(weather)
-Skarmory (loses offensive momentum)
-Ferrothorn (loses offensive momentum)
If we're worried about CM Arceus-Ghost, then perhaps we could look at Dialga again? Dialga forces Arceus-Ghost into using Focus Blast, which is extremely unreliable, and if they have no boosts, can phaze it out. 4 SpA Arceus-Ghost Focus Blast vs. 252 HP / 200 SpD Dialga: 168-198 (41.58 - 49%) -- guaranteed 3HKO is okay I guess but keep in mind that Focus Blast has a 49% chance of hitting twice in succession. Furthermore, Dialga can support the team by spamming Roar and taking advantage of the hazards set by Deoxys-S. This also draws in Fighting and Ground type attacks that Latios can take advantage of. However, for this round, I will most likely advocate for SD Arceus-Ghost.
This is of course under the MASSIVE assumption that said ghostceus is a calm mind variant. Sword dance variants don't care for any of cm ghostceus' checks/counters while support ghostceus completed its goal by luring in its cm variant checks/counters.





i may as well join in . .






