Suicune first appeared at a lake inJohto, where aGoldeen was feeling ill due to dirty water. Suicune used its power to restore the lake water Goldeen was in and heal it. Later, a group ofPokémon hunters started to deliberately pollute the lake in order to force Suicune to purify it again and again. By the timeAsh andGoh arrived, Suicune's repeated use of its purification power had left it low on stamina, allowing the hunters to seize it with nets and ropes. Desperate to save Suicune, Goh threw aPoké Ball at it andcaught it.
Leaving Ash to battle the hunters, Goh ran away to get Suicune to aPokémon Center, but tripped and ended up dropping the Poké Ball, allowing Suicune to get out. It froze its Poké Ball to avoid beingrecalled and climbed to a nearby tree to recover, so Goh started caring for it himself, treating its wounds and feeding itBerries to restore its stamina. When the hunters showed up again, Suicune witnessed Goh's selfless actions to protect it, and it agreed to fight by his side, quickly defeating the hunters andfreezing them in a block of ice, allowingOfficer Jenny to arrest them.
With the hunters apprehended, Goh offered torelease Suicune so that it could continue its journey, but it chose to remain his Pokémon. As such, Goh then brought it toCerise Laboratory and showed it toProfessor Cerise,Ren, andChrysa. Soon after, though, Suicune departed to continueroaming theworld, which Goh was perfectly happy with, as he felt that Suicune was still present in spirit.
InBig Brother to the Rescue!, Suicune temporarily returned to Cerise Park, where it helped to purify the water polluted byGoh's Grimer and restore order among the other Pokémon before departing once more. Before leaving again, Suicune acknowledgedYamper's efforts to keep Cerise Park in order.
Suicune is a kind and caring Pokémon. Like all of itsspecies, it has the power to purify dirty or polluted water, and is very dedicated to using this power, as seen when a group ofPokémon hunters exploited this sense of duty to force Suicune use its power to the point of exhaustion. Being aLegendary Pokémon, it's also very powerful.
Initially, Suicune didn't take kindly to Goh catching it, but upon seeing his selflessness in how he healed and protected it, it started to view him as worthy to be itsTrainer, even allowing him to command it inbattle. Despite this, however, it has not given up onroaming theworld to continue its task of purifying waters. It may still show up atCerise Park on occasion to watch over the Pokémon residing there, as shown by it having witnessedYamper's work at the Park.
