Dialga

Dialga's typing, bulk, and power allow it to remain a threat in ORAS Ubers; it is also capable of setting and keeping up Stealth Rock with ease due to its expansive movepool, which allows Dialga to deal with the common Defog and Magic Bounce users in the tier. The newcomer Primal Groudon does hurt Dialga's viability, however, as it can also fulfill the same role of a Stealth Rock setter and, because it comes with more perks, outclasses Dialga in some areas. Dialga's Ground-type weakness hurts its viability even more in a metagame dominated by Primal Groudon, and Dialga's lack of reliable recovery means it can be very susceptible to being worn down.