In a fight between Grey and Lizzy I think Lizzy has the higher chance of victory.
Why? Well, they are obviously both extremely talented at fencing:
If they were to battle each other soley based on skills their fight might continue until one faints from exhaustion.
Now, Lizzy has oftentimes proven just how strong she is, yet Grey is a brute who often resorts to violent behaviour which has had a training-like influence on his body, plus he’s a guy so he would hardly lose to Lizzy in terms of physical strengh.
The difference lies in their personalities:
To Grey hurting people is just a game he enjoys while Lizzy only fights for valid reasons. Grey wants to win and would do anything for that.
Lizzy on the other hand is the rational type of fighter. She has her eyes and ears everywhere and is therefore capable of dodging Grey, parading and counterattacking. She’s strong and equally fast, if not faster.
She can pose a threat to him and the idea of losing his own game would drive Grey furious. He’d become even more violent and completely obsessed with taking her down whatever it would take. Being the genius she is, Lizzy would see through this, find his openings and strike.
So yeah, brains over muscles in fencing.
( Haha, she’s the brain~ )