When a side battle ability activates, are both characters "in the side battle" simultaneously? Or does one enter, then the other?
For example, if I block with King Rehoboam and make my Jehoram (with Book of the Law active) fight my other green hero, can I use Jehoram to place a green enhancement on that hero before the hero enters battle? Therefore making the green enhancement activate immediately when the green hero opposes Jehoram? Or is the green hero in battle before Jehoram's ability activates?
King Rehoboam - Select any two Heroes in territory to fight each other. Losers are placed beneath owner's draw pile(s). Errata/Play As: Select any two Heroes in a territory to fight each other. Losers are placed beneath owner's draw pile(s).
Jehoram - If Book of the Law is active, you may place an O.T. Enhancement from hand or discard pile on a human Hero of matching brigade in your territory. The next time that Hero enters battle, that Enhancement activates and is discarded immediately.