first off you could combine HP and Mp scrolls alongside buffing them both. Mp just isn't useful enough on its own to justify the scroll slot (as in I've never seen anyone use one)
You could also look into combining both types of Def scrolls (While still buffing them.). I don't think they're useful enough even buffed that combining them would be too strong.
A third option would be combining all 4 scrolls together into something like a scroll for survivability or something. And yes I do think the individual scrolls are weak enough that combining them all together wouldn't be too strong, it would just be a matter of properly balancing the numbers.
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