This happened accidently in zelda, there was this old man by a relic for no apparent reason. I randomly told the man to go and pick it up knowing that he couldn't.
He did!
Not sure what is going on here but and old man seems to act like a temple and it can garrison relics into it. You cannot see if he is holding a relic or not but if you kill him, he will drop them.
You can modify the old men to carry unlimited relics too! I made an old man carry 96 relics at once!
However, I have also found that he cannot garrison them into a temple because it is garrisoned in him so you can only make the relics ungarrison.
This is a very strange discovery but if you are ever wondering why old men have 0/1 in garrison even though you cannot garrison into them Please comment on this trick.