Suicune, the Aurora Pokémon. It travels the world and purifies water wherever it goes, sailing on the North Wind.
– Ash’s Pokedex
Suicune is the 3rd of the legendary beasts (in Pokedex order), unlike Raikou or Entei, it doesn’t roam. It’s the mascot Pokemon of Pokemon Crystal, appearing on the box. One of the characters, Eusine, is obsessed with Suicune; he’s been chasing after it for a long time. So I wonder if he’s jealous that you end up catching it, haha.
Suicune played a decent-sized role in the 4th movie. There’s also a shiny one in the 13th movie. It seems that unlike legendaries like say, Palkia and Dialga, there’s more than one Suicune in existence.
Stat-wise, Suicune has more defenses than offensive stats, but since it’s a legendary, its Sp Attack is pretty good too. It’s a generally pretty bulky Water type, but has good offense as well. In the Dream World, Suicune gets Water Absorb, which would make it even better competitively.