City of RefugeOnce per turn, if an opponent's ability harms your O.T. human, you may hold it here instead.
If an O.T. EC that has been converted to a Hero is discarded by an opponent's ability, you can instead the SA to hold it in City of Refuge. Since you insteaded the discard, the card never hit the discard pile to reset and is still a Hero.
If an O.T. EC that has been converted to a Hero is discarded by the numbers, that's not an ability harming it, so it would be discarded and reset to face value.