By rights, the saber should cleave straight through Kevin's blade and, subsequently, straight through Kevin. It doesn't. If he weren't so angry, it would, but Kylo Ren has made a grievous error in that he has given Kevin a reason. A Kevin with a reason is a dangerous beast indeed and just now, he knows with perfect clarity what he needs to do. Between that clarity and the rage lighting up his sword, the blade is that much stronger, and it meets the light saber with a clang that wobbles in the air. Sparks fly from the impact, but it holds, and if he survives this, Kevin will make a mental note to do something good in the name of the witch who conjured the sword for him in the first place.

-- but, the girl first. Kevin snatches her out of the sith's grip and she wails as he retreats, making his location obvious. Some brave soul rushes forward to collect her and flees and Kevin reverses his direction immediately, heading straight back for Kylo Ren. He does not intend to give him the chance to engage in any more magic choking.