From GameWatcher: “For the longest time, endgame crises have been the bane of Stellaris players mostly new but also old. Revealed today, the upcoming Nemesis expansion will finally let us embody a crisis and sow a path of destruction throughout the galaxy, while also adding espionage tools.
The path to becoming a crisis in Stellaris: Nemesis starts by selecting its new Ascension Perk as your third, provided you’re not playing an empire with the xenophile, pacifist, or rogue servitors civics. Once you’ve picked it, you get access to a new interface showcasing your current crisis level, available perks, as well as a new resource to pursue: Menace.”
Source: N4G PC Stellaris: Nemesis Expansion Lets You Become the Crisis, Eat Stars, Also Adds Espionage