Imperage had no mercs because he didn't want them to be injured while making this "demonstration", thus requiring healing at a healer.
Locolive didn't lose health because Imperage probably dropped his weapon before the battle demonstration.
I just played the battle from his profile. To give Locolive credit, his mystic is really good at using Heal and Fountain of Life. Imperage did do some damage, but it was always healed by Locolive right away. That being said, this battle doesn't matter. There is nothing official about this thread,
it's just for fun. If these types of stats (gold won / gold lost) were measured in the game (which they might be at some point), then it would matter.