Geological / environmental event
The Gods go to shape the world of Telnoth. In doing so, they find the primal and mystical planes connected to them and shape them as well.
After planning is complete, The divines set out to shaping Telnoth. Chauntea and Grummsh are set to carving out the lands forests and topography, while Ehlonna discovers something of great import. She finds connections to realms associated with this place, and has Vecna aid her in shaping them. Vecna takes a liking to the cold Shadowfell, while Ehlonna shapes the vibrant Feywild.