Mokona is always with a strangly contented expression in his face. He is always afraid of enemies, so he disappears when the Magic Knights have to fight.
He is a seijyuu (the kanji for 'sei' doesn't mean 'spiritual' like the others, but means 'holy') that Princess Emerauld gave to Clef to be given to the magic Knights. Clef then, knowing that would not have time to give Mokona to the three girls, let Presea stay with that strange animal... With his gem in his forehead, he can produce many magic items, like the Mokona Capsule, which is used to fly or to dive, lots of food and accessories, a medical kit, the hotel-like tent or sleeping bags, and a map of Cephiro.
Umi is always running after him and is Hikaru's intimate friend. Mokona is always saying PU! but the three girls can solve what he wants to say. He helps the Magic Knights a lot guiding the girls to the Mashin's Temples or guiding them through the Forest of Silence, even Umi saying that he is useless when enemies appear... After Clef was turned into stone, Mokona is the only way that Clef have to communicate with the Magic Knights.
You won't believe, but Mokona is one who most changes from Anime to Manga on Rayearth 2. First, on the Anime, Mokona still fights with Umi, but teases Primera more and becomes a normal 'pet' for the Magic Knights. But on the Manga, he is something more important than what he is in the anime...
Voice Actress: Shiratori Yuri
Other versions:
Mokona wouldn't have his name changed, but on Mexico, his name changed to Mikona, because there, moco mean mucus and people would think that Mokona is made of mucus, instead of marshmallow...