Dialga Trio Raid Guide

Nothing in the game comes close to Primal Groudon in this raid. It's the king of DPS and TDO alike, and its Primal boost turns a number of the top Ground Types nuclear, especially in Clear weather. Add to this a resistance to Dialga's Steel Type moves and a double-resistance to Thunder, and it should be very clear why Primal Groudon is unparalleled. 

Mega Blaziken can't hold a candle to Primal Groudon... literally nothing can. So why is it up here in the Supreme Mega Evolution counters list? Because it's the best Fighting Type Mega Evolution in the game, meaning it provides a an extremely valuable boost to all of the best Fighting Types. This alone puts it just over the edge and makes it one of the two Mega Evolutions that are on the forefront of this raid. 

Mega Garchomp actually had higher average performance than Mega Blaziken, especially thanks to its triple-resistance to Thunder. However, it really doesn't appreciate facing down Dragon Type moves, and in practice it's basically a worse Primal Groudon.

While definitely below the competition as a Fighting Type, Mega Lopunny is still a decent backup Mega that can make Fighting Type teammates all the more useful in the absence of Mega Blaziken.

A good filler for a Ground Type team, Mega Swampert can help boost Ground Types in the absence of the all-important Primal Groudon.

Shadow Excadrill hits like a truck, and has its middling bulk patched up by the fact that it resists everything that Dialga can throw at it, even double-resisting Thunder. Add to this the fact that it can be passively boosted by just having Primal Groudon on the team, not even active, and it should be pretty obvious why Shadow Excadrill is the top non-Mega/Primal counter for this raid.

The top Fighter... has some issues here. It works extremely well in general, but its weakness to Dialga's Steel Type moveset makes it pretty easily picked off without some good dodge-timing. That's not to say it's bad by any means, but it's also not quite perfect.

Shadow Garchomp, much like its Mega forme, doesn't like Dragon Type moves. However, it's still a strong performer that can throw out extremely strong attacks while triple-resisting Thunder.

The one true vanilla Fighting Type, Shadow Machamp works well and has no major issues here.

While a bit worse than Shadow Machamp, it's still great.

While fairly high on the DPS chart, Shadow Mamoswine doesn't like facing down Dialga's Steel Type moves.

Baby Keldeo doesn't care for Thunder, but at least it resists Steel Type moves.

Lucario has a great set of resistances for this raid, resisting everything that Dialga can throw its way save Thunder.