I think that Isaac will become an anime-styled anti-hero. Because it has been foreshadowed in:

He definitely has the potential. He's sympathetic to Doorman's faction, which might very well be an enemy of the Activity Club. Forge indicated he was going to join said faction, and Spender's reaction implies he knows about said faction, but he had no issues with killing forge anyways. So if Isaac gets fed up with the activity club, he may end up throwing in with them; making him a pseudo-badguy. Especially if the storm spirit is as powerful as some people are guessing.

Oh speaking of the storm god. I'm about 75% sure it's Tlaloc or something similar. Which would make him both very powerful and very aggressive.

I have a speculation. I think I remember Zack saying that spirits are created and based off of people beleifs. Just like how Isaacs spirit was based off his beleifs of storm gods.

On one page, it is shown the Maxs mother makes scupltures out of scrap-metal.

Isaacs spirit is scrap-dragon. And he (...or she?) can cotnrol metal!!

Anyways, I think that Scrapdragon was based off of Maxs cynism and grudges throughout the years of his life.

An important point I think you're missing is that a Spirit is not necessarily created by the Spectral wielding it. The idea of beings like spirits coming into existence from or depending on belief of people is not a new one. Just look at Tinkerbell from Peter Pan for a good example. It would take a lot for a god to be brought into existence and I don't think the belief of a single person in the abstract concept of the god's domain would cut it. I think it would be pretty safe to say that the more people believe in certain Spirits, like gods, the stronger they become.

I'm not saying that Scrapdragon has nothing to do with Max's past or his mother, but I think it's a stretch to assume that Max made the Spirit. I imagine spirits forming as a sort of congealing of thoughts or emotions from many sources or even a single powerful source into a conscious entity.

I meant to say Maxs spirit is scrapdragon.

I meant to say Maxs spirit is scrapdragon.