Blueprint Function Library
Because there are plenty of objects on this game that can damage the player, it's useful to create a universal component that can be set into any of your objects in a few steps and that contains any kind of common function you need.
A Blueprint Function Library is exactly what we can use for this purpose: it's a collection of static functions that provide utility functionality not tied to a particular gameplay object. These libraries can be grouped into logical function sets.
We could put the function to kill the player into a library, and access this function on any object that has to kill the player when a particular condition rises. A ball, a spear, or a projectile are all different elements but all have one big purpose: kill the player.
Note
Actually, there's already an element that can be used (but not for our purpose): the Kill Z volume. This volume essentially destroys any Actor that enters (including the player) and is usually positioned at the very bottom...