Their decision

Lisa and Valdel's sword clashed and upon contact, Valdel could tell that Lisa's power was nearly equal to his own. It was true that the body of the dream Valdel was a bit weaker than his original body, but even then he wasn't expecting Lisa to be able to match his strength. 

The two attacked each other with a quick exchange of offense and defense. Their power and speed were nearly the same, being Valdel were a bit stronger, but Lisa was slightly faster. Since Lisa was faster and more dexterous, Valdel was forced into the defensive relying on parrying and countering her strikes. 

The Lisa in this dream world might have become stronger and had gained a lot of experience over the years, but Valdel did not only have his experience from the real world but the experience of the Valdel of this dream world, as well as his experience as Demon Lord Kir.