As Zelus's name suggests he is a rather jealous and envious little thing. Zelus will do anything to be picture perfect like his father, or so he thinks. Theres much more to this lad beyond what the eyes can see. A constant battle raging behind his eyes at all times, always challenging himself to push beyond expectations.
Ceruer, a fellow pup, constantly nagged and picked on Zelus, to which Zelus didn't react well to. Although to the rest of the pack, especially den mothers, Ceruer was a little angel. This made it hard for Zelus to cope as the pack never believed him, though his mother did. To which
Harmonia and
Circe had their own rivalry for a while due to their pups dismay.
Zelus like his father is very straightforward and sharp-edged.. like his mother his words flow from a golden tongue yet his legs carry him just as gracefully as a fish out of water. This was well known so it was believed that Zelus was lying due to envying Ceruer for being the cove's beloved pup who never did wrong. This in turn lead to Zelus acting out on multiple occasions, such as during a battling game the pups played he hurt another pup in an attempt to outshine Ceruer. This is when Faunus came to the conclusion that he needed to step up as a father.
When this decision was made Faunus decided to take on Zelus as his apprentice as he knew his pup better than anyone. Zelus trained beyond expectation daily with his father in isolation, this turned out to be the best decision that could've been made. Zelus had finally come to a calm state in which he didn't feel the need to outshine anyone, especially if that meant endangering a pack mate. Although he never could quite shake the feeling that there was more to why Ceruer was so mean to him..