I'm very sorry, but it is cant be tracked by event triggers like:
- Unit Dies (because Leoric actually is not dying)
- Unit Starts Effect of an Ability ... and all like this (begin casting or channels...)
Well, it can be tracked only by timer events that will check hero's hit points.
If it < 0.405 then create a dummy unit and give to it ability with target aoe dummy spell. to select ressurect position, start other timer for 3 seconds (hero's ability duration).
If position have not selected -> revive king at his death place.
That's all. Good luck, because i so laze to do it myself.