He never held back.
If there was one thing Mydei loved about having you as a sparring partner, it was the fact that, unlike many others before you, you could keep up. His punches and kicks would be met with matching ones in retaliation, the sound of metal clanging and swords clashing — a familiar noise by now.
"That's all you've got?" He asked as you delivered another blow, then charged straight at you once more. He didn't even remember exactly why he had chosen you when he did. He was bored, you were free and you didn't seem terrible at fighting, so he took the freedom to make assumptions. And his expectations were more than surpassed when he found himself with a bruised lip later.
Since then, it was always you that he would come to — albeit, begrudgingly — for a rematch. It was a thing he could actually look forward to, something to occupy his time and ease his stress from time to time. When things escalated and his fist met your face particularly hard, sending you reeling back down, that's when he stopped. For a moment, just a moment, something akin to concern and guilt washed over him before they were squashed down once more.
"Get up, come on. No slacking off now," and yet he still offered you his arm. There was an enormous difference between a mere rookie opponent and a real sparring partner — you.