For use with Tharros' Umbral Blade.
Tharros Strike on the attached build will be easily capable of fully stripping armor and shields, allowing you to hit raw health directly. Each swing will always apply Viral or Heat. You don't want too much Viral, or you'll never get the nice DoT proc of Heat and this is why not to use raw elements. Smite, of course, will double dip on DoTs as well.
Why not [Condition Overload]? You're free to remove an Umbral Slot and take [Sacrificial Pressure] off. But, if you're going to minmax an [Excalibur], you may as well use the base [Excalibur].