What Happens if you make a side battle with King Rehoboam and play Strife?
Withdraw all but one Hero.
You withdraw all but one Hero from the current battle. 
I agree, but I think that the confusion came from the concept of which battles are affected, which is why the question was posted.
To answer the question for all similar issues, in order to affect
any or
all cards in battle, the card must specifically say "field of battle". Otherwise, the special ability has a default condition of targeting the
current battle. That's why Strife, which has no "field of battle" component, withdraws only heroes that are in the current battle.
