Zombies. If they are your minions, they won't attack you, so all you need to do is poison a few water supplies with the parasite (proven by scienceto be the most likely form of zombie) and have an army that cannot be truly destroyed, if all water is infected. Then, join with a survivor group and use a mutated form of the parasite to make them very suggestible, and do whatever I say. Repeat until I have an almost unlimited zombie army, maybe even with leaders and labourers. Use the ensuing world peace to have zombie scientists build a new, immortal body for me, and space travel. Use a fleet to land on an alien planet (being immune to the environment because I'm already a dead robot... cyborg... zombie... thing) and create even more zombies. Spare a few with a similar worldview/ army of minions, and form a ruling council of a peaceful utopia with no war, as there is just one faction, and we're all on the same team. Keep tinkering with the parasite until you have a way to make normal people who just really love you, and infect everyone with that. So I'd have a human(ish) army, a robot army, an alien army, and they'd all be zombies. Is great.
