SHB BLM is the peak of this game's job design

[Seraphor]

F3 - F4 - F4- F4- F1 - F4 - F4 - F4 - F3 Proc (which you should have always) - Despair - B3. Repeat. Blizzard III can be cast with zero mana so you can do this just fine.
Oh and despair hits like an osmium truck, pretty sure it's the hardest hitting spell in the entire game. You can do it twice with manafont too xD, BLM is totally out of control.

Is this really the point of Despair?
Why does it refresh your AF?