In Adventure Mode, select [[Act V]] from the map and travel to [[Battlefields of Eternity]]. Search the for a single bird-like corpse titled [[Ancient Corpse]] and loot the lore item you seek. You will need to return twice more for all three lore entries. Note: Pay attention to your map location in the top-right of your screen--you can wander into the [[Crag of Eternity]] without even realizing it; if you do, turn around and return to [[Battlefields of Eternity]].