Blue Mage tank???

[Claire_Pendragon]

It's call sarcasm , the word Mage alone should be a hint that their traits would be either MND or INT based.

BLU historically used all stats for spells, you need a lot of HP for breath spells. some use STR, some use AGI, some your level, or enemies level.
BLU doesnt stick to just INT and MND.