In Pokémon Legends: Arceus, two phenomena make dozens of Pokémon appear at once: mass outbreaks, which are part of the adventure from the start, and Massive Mass Outbreaks, added by update 1.1.0 “Daybreak”. These are the best moments to boost your catch counts, finish research tasks and, above all, hunt Shiny Pokémon. This page explains how each one works, which species appear zone by zone, and your odds of meeting a Shiny Pokémon.

Mass outbreaks

A mass outbreak gathers Pokémon from the same evolutionary line in a single spot in the area. Four are visible at a time; each time you defeat or catch one, another appears, up to a total of 10 to 15 Pokémon. An area can only host one mass outbreak at a time, but several areas can have one at the same time. You can spot them on the Hisui map, when you choose your destination, as an icon showing the face of the species involved.

The game rolls for outbreaks when you return to Jubilife Village: each area has a 20% chance of generating one. When you leave, each area except the one you are heading to has a 20% chance of losing its outbreak. The species, their stats and whether they are Shiny are all fixed at the moment you arrive in the area. An outbreak can also hold an Alpha Pokémon: the probability is 0.99%. To learn how to handle them, read our page on Alpha Pokémon.

Species encountered, zone by zone

The Obsidian Fieldlands

The Crimson Mirelands

The Cobalt Coastlands

The Coronet Highlands

The Alabaster Icelands

Massive Mass Outbreaks

Massive Mass Outbreaks are storms or, in the Alabaster Icelands, blizzards that make 11 to 15 mass outbreaks appear at once in an area. They have only existed since update 1.1.0. They trigger once you have completed mission 102, “Daybreak”, after the series of investigations in missions 95 to 101 that you carry out in each area with Ryza and her Munchlax (see our page on side requests and the one on the “Daybreak” update).

Munchlax.

A Massive Mass Outbreak is time-limited: it lasts 7 minutes in 75% of cases, 9 minutes in 15% and 11 minutes in 10%. The game shows warnings as time runs out, up to the message announcing the end of the storm. Once time is up, all the Pokémon disappear.

What can you find in a Massive Mass Outbreak?

  • The first wave has 8 to 10 Pokémon per site.
  • Some outbreaks are marked with a star once revealed: after the first wave is cleared, a second horde of 6 to 8 Pokémon arrives. It is made up either of evolutions of the first wave (81% of cases), Alpha Pokémon of the same species (10%), or Alpha versions of the evolutions (9%).
  • An outbreak marked with a Berry drops an Aguav Berry every time a Pokémon is defeated or caught.
  • The Pokémon you meet are at least level 60, except for species that evolve at a specific level: their non-Alpha specimens are found one to three levels below the evolution level.
  • Those in the second wave always have at least three perfect individual values.
Massive Mass Outbreak typeFrequency
Standard76.5%
Hidden bonus (second horde, not indicated)12%
Aguav Berries8.5%
Star bonus (second horde)3%

Each Massive Mass Outbreak thus includes a “rare 1” site, a “rare 2” site and common sites: they are not all equal, and the most sought-after species are concentrated on two sites per area. You can’t know in advance which species are present. To find out, go to a base camp in the area and give 5 Aguav Berries to Ryza’s Munchlax: it will reveal all the outbreaks on the map.

Species encountered, zone by zone

The Obsidian Fieldlands

The Crimson Mirelands

The Cobalt Coastlands

The Coronet Highlands

The Alabaster Icelands

Shiny Pokémon: the odds

Outbreaks significantly improve your chances of meeting a Shiny Pokémon. The following table gives the rates recorded for the game, with the Shiny Charm and with a perfect research level for the species (see our page on Shiny hunting).

SituationWild PokémonMass outbreakMassive Mass Outbreak
Base1 in 4,09626 in 4,096 (1 in 158)13 in 4,096 (1 in 316)
Research level 102 in 4,09627 in 4,096 (1 in 153)14 in 4,096 (1 in 293)
Perfect research4 in 4,09629 in 4,096 (1 in 142)16 in 4,096 (1 in 256)
Level 10 and Shiny Charm5 in 4,09630 in 4,096 (1 in 137)17 in 4,096 (1 in 241)
Perfect and Shiny Charm7 in 4,09632 in 4,096 (1 in 128)19 in 4,096 (1 in 216)

The rate for a Massive Mass Outbreak is lower than for a standard mass outbreak because it contains many more Pokémon: overall, though, you multiply your rolls, and the game warns you with a chime when a Shiny Pokémon appears, even far from you.

Tips for making the most of outbreaks

  • Let the Shiny Charm and research levels do their work: update your tasks before heading out.
  • Prefer an outbreak featuring a species you’re missing so you can complete its research tasks; our page on the Pokédex and research tasks details the milestones.
  • In a Massive Mass Outbreak, start with the star sites: the second wave contains evolutions or Alpha Pokémon.
  • Keep Aguav Berries in reserve to reveal the sites: outbreaks marked with a Berry drop them, so you can restock yourself.

For the complete list of Pokémon you can meet in each area, open the Hisui Pokédex.