Captain Olimar
Olimar is traveling through space while on an interstellar vacation when his ship is hit by a meteor and he crash lands on a mysterious planet. Since the Oxygen in the atmosphere is poisonous to Olimar, he must repair his spaceship and escape before his life support runs out in 30 days. From Olimar's daily journal we learn that he is a family man and knows next to nothing about how his ship works.
Pikmin
These strange creature have both animal and vegetable characteristics. They take an immediate liking to Olimar and will usually follow him around wherever he leads. Pikmin start life as a seed produced by what Olimar calls an onion. When the seed sprouts, it can be plucked by Olimar to get a Pikmin. When Pikmin encounter food (colored pellets and the corpses of enemies) they will carry it back to their onion when prompted by Olimar, which will then produce more seeds. If left in the ground, Pikmen will gradually mature from leaf stage, to bud stage, to flower stage; the more advanced stages move more quickly. Pikmin come in three colors.
These Pikmin have pointed noses, making them stronger fighters than the other color types. They are also immune to fire.
These Pikmin have large, wing-like ears which allows them to be thrown higher and farther than other Pikmin. They are the only Pikmin who can handle Bomb-rocks.
These Pikmin have gills, which make them the only kind that can survive in water.