Mildly Darkened One
104-ish: Kardashev curve shenanigans. The invasion is about ego - a compulsive need to show superiority, to dominate, to hurt people who don't bow and scrape.
The invasion is one person.
Mind, even with AI enhancements and advisors, the Invader is just one person. They're nowhere near as smart as they think they are, and humanity stands a very good chance of being able to outwit them...