something that could explain it is that while her mana regen is high she has next to no mana pool to start up simultaneous spells and the armor fixes that by acting as an external storage, but still ofc the issue then comes up of why not use the regen to feed the armor or just chain spells one after another which would make the armor arguably mootDidn't she say she uses magic around her instead of storing it in her body like normal magic users do and that she essentially can't run out of magic power?
Did the author forget what was established just one chapter ago? That power meter should be always displaying zero (or near zero) for her, but it should also be irrelevant to her.
Yeah i know it's literally for the plot. But sometimes i wish he'd realize it sooner than later that using heavy weaponry is the proper way outHe really need to stop that habit of leaving the heavy weaponry for last in a life or death situation.