So if I block With Crimson King Rehoboam and create a side battle while You will remain is up, then Strife all but one of the heroes in the side battle, can my opponent use You will remain to add a hero still? There was a hero left, and the last hero wasn't removed from battle, either. I would think that the hero in the side battle would be considered the last hero, who left the battle through game rules.
King Rehoboam:
Select any two Heroes in territory to fight each other. Losers are placed beneath owner's draw pile(s)
You Will Remain:
...If an opponent removes your last Hero from battle, you may remove this from the game to add your Hero to battle.
Strife:
Withdraw all but one Hero.