Elessa was a young Wood Elf Scout that left Athel Loren in search of adventure, ending up fighting in the Great War Against Chaos along with the Imperial army and saving Emperor Magnus the Pious from a conspiracy early in his reign. 
The life of a Wood Elf is meant to be spent in service to the forest of Athel Loren, protecting it from those that would do it harm. However, some Wood Elves, known as Windborne, are born with an urge to wander, an overpowering curiosity and desire for adventure. Elessa was one such Elf and while vexing to her elders, these knew that she may become a great ranger if her adventurous nature was tamed. And so Elessa was given a small time of leave, no more than a hundred years and a day, to explore the Old World before returning to Athel Loren and taking up her duties.
Little more than a year into her travels, Elessa found herself in the Empire of Man. While stalking a group of soldiers in an army camp, she heard tales of Asavar Kul, the Everchosen of Chaos invading the Old World from the North and how Magnus the Pious had rallied the divided Empire to oppose him. To Elessa this sounded just like the epic adventure she left home to find. Thus that night she infiltrated Magnus' tent and offered her services as a scout. Impressed by her skills, Magnus accepted her into his retinue and Elessa helped guide the army thru the northern Empire into the frozen land of Kislev, which was under attack by Asavar. Elessa fought in the final battle at the gates of Kislev. She kept close to Magnus and was part of the heroic charge that slew the Everchosen.
Elessa returned to Nuln with Magnus, who was soon to be elected Emperor, to a hero's welcome. But the noise and bustle of the busy human city wore on her, and she began wanting to wander again, to leave the city and search for a new adventure...
- 1: Warhammer: Chaosbane