Key: SSJMatt2
Character: Nero
Skill(or transformation): Cosmo Tier 3

How well do you know the source material? (obviously not relevant if it's a transformation): I know Saint Seiya well, read all the Manga and going to watch Lost Canvas soon
Reasoning:
The main reason is due to a few character changes that Nero is going through. Meeting new and old people, he is changing into a more mature individual and with each near-death experience, comes away learning something new. With the Constellation of the Cygnus, he understands that he needs to train his skills and connection with his Cosmo, he isn't anywhere to the level he wants to be, especially for those he is close to.

Those people include Seraphim, Cracker, Velone, Blue, Marco, and a few others, but the most important is Nebula, someone he has been around a lot while training at her castle. She is currently far more powerful than him, but he won't stay that way for long.

The last battle with the two Kaijus and their followers prove to him that, many nonhumans are far more powerful than he is. Nebula is still working on a Serum, but it is his one true goal to become a Gold Saint, to help restore the reputation of the Saints and use his powers for the good of humanity. His character will likely to continue to develop, but he is shaping up for the future.

What is the moment: There is no real moment with this, but there may be in the future.