Reincarnated in Another World, Immortal and Undying as a Witch

The second part of "Reincarnated in Another World: The Undying Witch"

After reincarnating as an unremarkable commoner, I secretly followed the hero from behind all the way until he defeated the Demon King. I only came out to applaud them and say, "That was quite a show!" But they mistook me for the mastermind behind everything. The girl I once saved turned out to be a summoner who could summon the Angel God, one of my subordinates was the Demon King, my trusted demon general was at my side, I rescued an ancient demon god from its seal, and I was a necromancer who could control the power of death.