Indeed, his form was that of a child. He looked very similar to the Worldwalker when he was around fourteen. He had the same face, but his hair was brown instead of blonde and he was much taller.
Still, he looked like a young child, which made the expression on his face hard to fathom.
That kind of malice, resentment, and envy simply couldn't exist in someone of that age.
But, of course, the Dark God was not fourteen.
Damien felt it as well. When he became closer to the peak, his form changed somewhat. He became the version of himself that he saw. In essence, his mental image of himself became reality.
As Damien was someone who always remained confident in his sense of self, not much changed. Rather than someone in his early thirties, he looked like someone in his mid-twenties.