To participate in either of these events, players will need to download the latest Poké Portal News. If players have connected their Nintendo Switch system to the internet while playing Pokémon Scarlet or Violet, this will happen automatically. Players can also manually download the Poké Portal News by selecting Poké Portal from the X menu, and then selecting Mystery Gift, and then Check Poké Portal News. A paid Nintendo Switch Online membership is not required.
Face off against Eevee with the Mightiest Mark
This event's Eevee has the Normal Tera Type. Like all Mightiest Mark Pokémon, this Eevee can only be caught once per save data. While it may appear again in other events or be encountered in different ways in the future, players who catch it during this initial run will not be able to catch it again during any subsequent events.
Black Crystal Tera Raid Battles contain much stronger Pokémon than those appearing in ordinary Tera Raid Battles, and give out better rewards. Players who have completed certain postgame events will be able to start the Black Crystal Tera Raid Battle simply by walking up to and interacting with the Black Tera Crystal in-game. In the overworld, the Black Tera Crystals associated with these raids can be differentiated from other Tera Raid crystals by their aura and black sheen. Both are also clearly visible when looking at crystals on the map. Players who haven't yet completed the required postgame events can still participate in these Black Tera Raid Battles, but only by joining with other Trainers in multiplayer, such as by using a Link Code. A paid Nintendo Switch Online membership is required to participate in Tera Raid Battles with other Trainers online.
In the lead-up to Eevee Day, Eevee will be more likely to appear across both Paldea and Kitakami, the latter of which you can explore in the Teal Mask part of The Hidden Treasure of Area Zero DLC. While the Kitakami parts of this event are exclusive to DLC owners, players can still participate and catch Eevee in Mass Outbreaks in Paldea in this event even without access to the DLC.
Eevee encountered in the Mass Outbreaks in Paldea are more likely to have the Jittery, Intense, Intellectual, or Flustered Marks, while Eevee encountered in the Mass Outbreaks in Kitakami are more likely to have the Rowdy, Excited, Calmness, or Unsure Marks.