Wasn't sure where to put it, since not a it's not just arena or AI or something else.
Little background. I was fighting Divine Glory the other day with Adrenastaves counter presented in her Oracle thread (http://elementscommunity.org/forum/divine-glory/oracle-divine-glory/). The interesting thing is that whenever I got EM from that fight, I'd always receive a 122 electrum.
(http://i.imgur.com/NjtjgzQ.jpg)
Now, first thought that comes to mind is "Doc lied and used something that has either SoD or Stone Skin", which would explain everything, if I actually lied, but I didn't. So, I had to do a little brainstorming session.
Took a while and few battles against Serket with PDials, but I think we might have a hypothesis on this problem. See, when you fight Serket with PDials, you have a very high chance of collecting over one hundred poison damage on yourself. And when that happens, game decides to turn all this 100+ damage into healing (SoSacs and whatnot), and while only for a heartbeat, your current HP blinks OUT of boundaries of your max HP. You can try that, it works in trainer.
So, what does that mean for us? If something like SoSac can blink your current HP out of boundaries of max HP, can something else (http://elementscommunity.org/wiki/Druidic_Staff) do that? Apparently, yes. You see, there's a very special fact about Druidic Staff's regeneration ability - it actually comes BEFORE weapon attacks. How I'm so sure? Try getting hit by a 1 HP arena deck that only dealt like 2 or 3 damage, and then get EM. Druidic staves will grant EM, while life draining spells (http://elementscommunity.org/wiki/Drain_Life) or creatures (http://elementscommunity.org/wiki/Minor_Vampire) won't.
It's easily explainable by the fact that vampires and life-draining spells heal you depending on their damage, so they should calculate their attack first and then heal you. Staves heal you the same amount of HP, regardless of whether or not they hit anyone (Try going against :aether stall with adrenastaves),
which gives them opportunity of healing before attacking
With that in mind, we have a weapon that heals before it attacks. And since delay last only a split second, it most likely just doesn't give game enough time to "realize" that player's max hp is lower than his current hp, which results in player getting EM score for 105 HP as oppose to 100 HP, which apparently only differs in two coins. And no, anything else doesn't work, we can only have 2 coins above our average EM (though SoDs and Stone Skin are still a thing)
Tl;DR - Druidic staves give you slightly (2 coins) bigger outcome when facing 1 HP decks or Divine Glory. Go exploit that ;)