Zelos was the Frog specter of the XX Century. He croaks like a frog in the manga.
This frog specter, is a weak warrior that is the biggest Pandora to-do. According he, Pandora is beauty, but is as creepy as beauty. Zelos is a Radamanthys hater, because he is not a fan of Pandora, and don't like to follow her orders, and love sees Pandora huffs her enemies; as a terrorist specter, he must follow orders of a Kyoto, but he is sarcastic with everyone that disrespects Pandora, even with a Kyoto (but even so follow his orders); he always follows Radamanthys orders, but asked "Pandora will not get's angry with this?". So, he flatters the boss of his boss, to get advantage on him. He finds himself superior to all.
Although weak, compared with otherterrestrial saints, is a strong specter.
Zelos was based in Toad, a classic Marvel villain.
Zelos sends a group of 20 terrestrial specters of the 12 Temples of Athena; he don't trust in their success, but, how Radamanthys wished this, and Pandora will punish him after the files, Zelos sendsthem immediately.
After, he watches Pandora punishes Radamanthys happy so much. When Camus, Saga and Shura arrives at the castle, they order Pandora to allow they take the Athena's body in Hades Palace and meet him in person, and Zelos (as always together Pandora) advocates Pandora and rebuke the 3 because their vulgarity, and Camus freezes him to disturb. Pandora goes to Meikai and Zelos (already weak after various battles and near the dive time) recovered tramples Camus want avenge on him. But, Hyoga arrives and say "That man who trampled was my sense" and Zelos (in the anime) tries to get away, but Hyoga defeats him with his cold air; in the manga, he tries to fight against Hyoga (Radamanthys was getting away with no help Zelos, because as said Zelos, "The orders of Pandora must not be disrespected"), but is defeated.