Ugggh. Hate those Ankhs. Aknhs and Cannons deal 40% Morale damage I think? The Ankh Cannon deals like 80%. (Of your current, not Max. You can't die from these)
And about that final boss, the final boss is optional actually. You don't NEED to fight it. Just a heads up if you get that far and fight it, then cry because it's nigh impossible...
If your units hit 0 Morale, besides Yggdra, Milanor or a selected unit (Some maps have as a defeat option a certain unit, or ANY, unit cannot hit 0 Morale) they will Withdraw. This causes them to lose all REP (But you lose REP if you lose a clash) and they lose all current EXP, called a 'Zero Reset'.
It's in your best interest to never have your units hit 0 Morale.