Mega Evolution is back in the limelight with "Pokémon Legends: Z-A," and the "Mega Dimension" DLC is a colossal expansion of this gimmick. This update brings with it a whole new set of powerful Mega Evolutions that are linked with certain quests, Ranked Battles, or encounters with Hyperspace Fossils. It does not matter if you are looking for sheer power or for Mega-hunting; you must know where to look for each Mega Stone.
A list of fully detailed information about each new Mega Evolution that is available in Mega Dimension is provided below:
Mega Raichu X and Mega Raichu Y
Mega Raichu is here with two new forms, namely X and Y, keeping their Electric type intact. You unlock Mega Raichu by completing Side Mission 139: The Dauntless Raichu Duo. This side mission is found in a random yellow Hyperspace Flinger, and it is available only once you have completed Side Mission 2 and Side Mission 108. It rewards you with either Raichunite X or Raichunite Y.
Mega Baxcalibur
Mega Baxcalibur starts with a terrible Dragon/Ice type combination. This Mega is unique since it is only for Ranked Battle Season 4. It rewards players who excel in battle.
Mega Chimecho
Mega Chimecho evolves into a Psychic/Steel type. You get the Chimechite by defeating a Rogue Mega Chimecho that is hidden in a random 2-star Hyperspace Fissure with a yellow marker.
Mega Zeraora and Mega Lucario Z
Both Mega Zeraora (Electric) and Mega Lucario Z (Fighting/Steel) are confirmed to be added, but their unlock mechanics are still to be confirmed. These Megas will likely be added through events or quests in the future.
Mega Absol Z
Mega Absol Z is characterized by its strong Dark/Ghost type. Its Mega Stone is accessed by defeating Rogue Mega Absol Z in the Hyperspace Lumiose Survey No. 1 quest.
Mega Crabominable
Mega Crabominable gets a Fighting/Ice typing and can be evolved through the completion of the Rogue Mega Showdown Side Mission, allowing it to receive the Crabominite.
Mega Scovillain
Mega Scovillain keeps its Grass/Fire type. Defeat Rogue Mega Scovillain through a random 2-star Hyperspace portal to obtain the Scovillainite
Mega Staraptor and Mega Tatsugiri
Mega Staraptor (Flying/Fighting) is unlocked with Hyperspace Lumiose Survey No. 2, whereas Mega Tatsugiri (Dragon/Water) is obtained in Survey No. 3 after defeating their Rogue Mega forms.
Late-Game Megas
As you progress, Mega Golisopod (Bug/Steel) is found in random 3-star portals, Mega Meowstic (Psychic) in Survey No. 4, Mega Heatran (Fire/Steel) in Survey No. 5, while Mega Glimmora (Rock/Poison) is found in random 4-star portals.
Finally, Mega Darkrai is unlocked via Hyperspace Lumiose Survey No. 6, among the easiest of Mega species to get. The Mega Darkrai Mega Stone can be obtained by defeating it in a Rogue Mega battle in Hyperspace Mission 11.
