Era beginning/end
The Greatest Tree, Hildevrand, is cut down
This is when a coalition of all Human races assembled in the Vale of Cartoum to cut down the oldest, mightiest tree in the world, Hildevrand. Under its boughs had flourished the greatest civilizations of the Immortals, and its death struck a great blow for humanity. After this point it was really on. The Immortals started to (sort of) work together. Their aim became the final extinction of humans worldwide. Well, we obviously need to reciprocate the sentiment.