Mulu (ムルモ/Murumo) is Mirmo's younger brother. He lives with Kyle who is a rich boy. Mulu likes Katie when he first met her. Mulu is very cute but under his cute face has a naughty and scary attitude. He comes out of the purple mug. You need to pour tomato juice in the purple mug to call forth Mulu. He uses snare drum. He has a height of 8 cm (centimeters). He loves marshmallows.
Mulu is an immature, cute little Muglox who is Mirmo's younger brother. Mulu loves marshmallows and uses his personality to relax or manipulate others. He is selfish when it comes to marshmallows, and would do anything to make Kyle give him some (even telling him about Katie and Dylan's dates). "Deshu" (the most common phrase) or "Mashu" is his common phrase. At times, he is kind and sweet to his friends and is willing to help them when they are in trouble. When he is angry, he uses his antenna beam on his hat. Mulu has a female rival called Papii. Papii has a crush on him sometimes, and may be he also has a crush on her too. He gets crazy to Papii. Also Papii likes Murumo but doesn't have the courage to tell him.
Mulu learns the way how to fix the magical heart in Episode 7. In Episode 8, Mirmo and Mulu decided to duel using butt shakes. When he lost, he was really depressed but Mulu goes in Sasuke and Hanzo's trap while Mirmo goes in Yatch's trap. When he goes out of the bag, he then saves his brother and Katie and Dylan finally found him. In Episode 9, Mirmo and Mulu find anywhere for Mulu's partner. Mulu doesn't like a guy but likes a female partner. When Kepapa tried to match Mulu and a girl's compatibility, it comes to -150%, much to Mulu's disappointment. When Kepapa finds the correct boy, they saw Katie, and they thought it was Katie who will be Mulu's partner. But Kepapa said that it was Kyle, not Katie, who was the playboy. Being so much envious, Mulu hated to live with him. When they tried to match Mulu and Kyle's compatibility, it comes to 100%. Mulu is very disappointed when he finds out that Kyle is the perfect partner for him. Katie insists Mulu to be Kyle's partner. Mulu then says ok, just for Katie.
He also becomes golden Muglox in here.
Kyle uses Mulu for crystal collecting session. He uses his magic to collect crystals. He wishes that he is swimming in marshmallows.
On one episode, Mulu was following to Kyle, which was chased by the girls.