@Little Bird I get you and your idea is completely valid. We could use Personnel as a sacrifice, and negate an invasion. However, it would negate one of the most important and central aspects of Nocturnal Memoirs - the battles. I am leaning away giving anyone a way to escape a battle via game mechanics. Instead, I would rather you deal with a battle in a roleplay sense. Fight it head-on, have an ally help you, cut a deal, kidnap the enemy so they're forced to back off. There are a miiiillion ways to tackle an invasion that are a million more times more satisfying to go through with than simply using a game mechanic to 'skip' it.
Outside of spending for upgrades and invasioms (which is also accomplished via Wealth) what can we legitimately do with Personnel to validate it as a separate mechanic?