Well, it's got the power of forcing one's will against its self. Wow, wow, wow, put down that fork! I'll explain it to you:
Morgan's got a passive RW that's capable of making one's wishes into being. Originally, the power was manifested into an app, and needed to be willingly (albeit not necessarily intentionally) activated.
But, after she gained power (but not even close to the ammount of power she was granted in this fight), the app started to run alone. By then, instead of
making one's wish come true, it was already
forcing it into reality itself. That's it, forcing. The wishes have no need of being actually made, but the mere image or thought of what could possibly be a wish will trigger a chain reaction.
I mean, you wish that you defeat your opponent, even subconsciously, the spell is so powerful, it amplifies that wish and makes it so.
Now: In
The Librarians, there's a thing called "The Rule of Three", a multidimensional law that rules over all magic users. That rule is what's going to be the big deal here.
When the wish's granted, the Rule of Three brings it back into you.
So, the rule of three amplifies the spell, for good or bad. Any direct harm you do unto others with malicious intent will be visited back upon you threefold.
That said,
SBA dictates that all characters are
willing to kill. That mere feeling would be far enough to trigger the spell and, by extension, unleash the power of the Rule of Three upon the Mage. Regardless of what is done to Morgan, it will go back upon the Mage threefold.
That situation would most likely end in an "Inconclusive", IF Morgan was not an Immortal (aka Type 5) and hadn't got resistance to higher-dimensional EE.
With that, my vote's ultimately going to Morgan Le Fay.