Another interesting lore detail, in the new cutscene in which Vyranoth leaves Fyrakk, he says (looking at Larodar, the grove keeper being transformed by fire): "Imbued it with the living flame. The very flame we will use to infuse the heart of their precious world tree."
So the "living flame" is what he wants to use against the world tree, specifically to imbue its heart with it. We now know it turns something living and verdant into a large and blazing monstrosity, essentially.
Not sure if there's a connection, but the Evoker spell Living Flame can deal damage or heal, and is of the Red and Green flights.
So is he essentially looking to set the Emerald Dream ablaze? Or just turn all its denizens into his own army to use against the Titans?