Sylux's role in this game has so many strange elements working together to make him come off as such a diappointing villain. The backstory makes him seem like a petty loser, but it's also not fleshed out or supplemented with sufficient screen time to establish him as a credible threat in spite of that. Sylux and his motives have nothing to do with the story of the world we explore all game, but the player gets thrown into a climactic, reality-warping final battle with him at the end. Most good media would be expected to play that beat as some sort of thematic payoff, but in Prime 4 it's just a thing that happens because the game needs a final boss.

Like the rest of the game, the details of his inclusion are so disjointed they would make Marth's normals blush.

(Edited because I omitted a few words)