Mylor is one of my favorite summoners to use in low mana battles. I use him with stonesplitter orc who also retaliates. Thorns and retaliation are dirty together.

Death has some really good ranged attackers and a few good magic attackers. And using them makes Mylor pretty useless. If I see Mylor, I'll try to have a healing tank, like Haunted Spirit and then lots of ranged debuffers.

You chose well for the battle you showed, I think. I'm curious how things would have turned out if you placed the Shadowy Presence in the first position. That would have effectively killed the thorns for the first round or so of the battle. You would have sacrificed the 2 damage the Haunted Spirit did in round one, but it might have helped you last longer if the opponent gave you a harder time. I'm not sure about that, though.