Ozma Mount

[Mirakumi]

If I was a betting man I would say only the
Sacrifice L action works, because why else would they mention that one.

Well, that one as a last resort HOPEFULLY.
Your probably right But I'm just thinking since Absolute Virtue in FFXI was THEEEE longest battle - https://www.destructoid.com/final-fa...at-99391.phtml

You'll be able to use the rez one too - since the logo resurrection can be cast only a handful of times. And with that many people, there's going to be a lot of deaths so I doubt sacrificing one's self would come into play unless it was a must to avoid certain mechanic.