Knights of Tezoth

In terms of application, it is a normal spell. You can cast a conditional fireball, or you can cast something like this.
You won't even know.

When to cast? During battle? So if you cast this thing during battle, then after that battle someone (whoever is the "mvp" in some Revan's opinion) among the survivors will die, is that it? And can the Sith himself die? And what if you cast this thing three times per battle?