The detection of the activation of a Reincarnation-based skill is somewhat complicated, so I have decided to post a test-map I have had on my computer for some time now.
This method is based on two events: "a unit dies" and "a unit's hp becomes less than 0". Reincarnation occurs whenever the second event occurs, but the first one does not.
Only one problem is left: I am unsure if a unit dies when it's hp drops below 0 or below 1; if it's below 1, then my triggers would fail if a unit's hp were to drop to, for example, 0.5, as the unit would die then, but the second event wouldn't fire. Similar problems would also occur if a unit dies when it's hp drops below 0, but I would be using the event "hp below 1". So, I am in a dillema which of these two events to use, and I hope someone who knows this can clarify at which point a unit dies, when it's hp drop below 1 or 0? | 
I was planning to do this for some time luckily I didn't begin yet ;) .