The Dark Lovers are Gaito's servants. Each one was created from some type of sea creature.
Izul - Izul is probably the most devoted of the Dark lovers. From the start she did not trust Sara. Her powers include the ability to control the ocean's waves, the ability to summon storms, the ability to control various ocean beasts, and the ability to summon dragons made of water. She was originally a Shark.
Maria - Maria is the closest to Gaito (Romatically), however, she's the most cold. She basically only sees Gaito as her boy toy. That may be why she's his favorite, because she's cold. Maria's power is ice. Her main offensive attack is a barrage of flying icicles and she also can control the wind. Maria was a Eel. (btw, she looks REALLY cold in that pic, right? *sweatdrop*)
Eriru - The best way for me to describe Eriru is split personality crisis. Most the time she's all cute and bubbly, but when she switches personalities, she's really dangerous. Eriru was originally a Manta Ray.
Yuri - Yuri is the youngest of the Dark lovers (and she's absolutely adorable...). Because of the fact that she's still just a child, she's not as set in her love as the others...in fact she develops a bit of a crush on Hippo. But when alls said and done, she chooses to remain loyal to Gaito. Her most powerful magic comes from playing the piano, and she was originally some sort of tropical fish.