- 19 Apr 2017 11:38
#197279
It's a combination of things. Simplest way to put it, it's based off available spawn location, every so often (think it's a few minutes) pixelmon tries to spawn a legendary, the legendary that spawns is dependent on which biomes are closest to the player.
Each legendary would have an equal spawn chance. Since there's 4 different ocean legendaries, they're the ones who spawn more often.
Basically, if you're on an island with sunflower, beach, and ocean/deep ocean biomes, there'd be a 1/6 chance of rayquaza to spawn, 1/6 chance of suicune to spawn, and 4/6 chance of a water legendary like lugia or latios to spawn.
It gets a bit more complex when one considers if the biomes have legendary spawn points and if the legendary has been spawned recently (depending on the settings, there's a cooldown for the same legendary to spawn again). If you search online, there should be more details describing this.