The main quest is the archetype quest (this is a world exploration game)
The side quest is the versions of lives. Dr Strange lived a life and the person of that life would become the archetype's persona, these side quests are irreversible. Since each of them is irreversible, the main quest is going to be left off with whatever power / level the persona had.
There are multiple irreversible lives that Dr Strange could live and so would there be versions of him that the archetype could transform into. However try to specialize into different stuffs each time, that way you could had access to more techniques. If one life turned out to produce so weak persona, then maybe in the other life you might do everything the same again, but this would leave two personas doing the same thing and you would ended up having to scroll through two redundant transformations everytime.
Even when a persona was weak, in the main quest they would be useful because each transformation give each other "perspectives" upon which they could rest or setting up their investments, etc. Sometimes the weak persona is needed because its weak.
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Thought of this after playing FFVII REMAKE. So good game
