Good catch by the way, I completely missed that.
To be fair, there isn't really any good domain in the 5e PHB for clerics of a necromancer god. Perhaps they chose life domain because necromancy == manipulating life energies? Still, the light domain's overall theme is healing and radiant damage, which is the exact opposite of what I'd expect from a cleric of Myrkul.
Perhaps they'll add a more fitting domain later on? Death domain from the DMG would be a good choice.
