Yes, a majority of readers preferred the usage of items over links when it comes to combat in the Homo Perfectus series, and variables don't kick in until links are used (meaning that if Health reaches 0, you'll only die the next time you use links) is a side effect.
Anyway, you could have just messaged me, but the enemy you're talking about is not just a copy of yourself, it's a live mirror reflection, and he moves in exact coordenations with your own moves. This of course means that you can only hit him if he hits you, because if you dodge, he dodges in the exact same way (and any attempt to counter the dodge will he do as well and so on and so on). You loose exactly as much Health as he does, so even if you defeat him, that means you're defeated as well.
You have to find a way to make this mirror reflection of you stop fighting. Wonder how you could ever do that?