In 339, Queen Esaelle died of an unknown illness. She was brought back to life thanks to the Staff of Yresse, created from the sacrifice of the dean of the forest, the great red oak Yresse.

In the year 339 of the first era, the kingdom of Irendille experienced one of the saddest episodes in its long history. The great Queen Esaelle who reigned with King Irendille was struck by an unknown illness, something never seen in wood elf country. The illness took him away, plunging the king into insurmountable grief. The news of Esaelle's death reached the heart of the forests of Irendille, the news was terrible. The great immortal Queen Esaelle among the immortals was no more.

The king could not accept it, he summoned all the wise men of the kingdom. After days and nights of searching, a glimmer of hope appeared: an old treeman in the kingdom explained to Irendille that a very old story among his people spoke of a staff made from a treeman. The story explained that if the oldest tree-man in the kingdom agreed to sacrifice himself so that his heart could be made into a staff, we would have the most powerful healing object the central lands had known. The entire assembly of wise men fell silent and all thoughts went to Yresse the great red oak, dean of all the tree-men of the kingdom. The stories say that he knew the other world, the one before the great upheaval.

Irendille left the next day to meet the big red oak. He stayed four days in the forest and returned with the heart of the tree. The old tree man had spoken the truth, the power of the staff was immense, and Queen Esaelle was brought back to life. King Irendille gave the name of the large red oak to the staff: the staff of Yresse. He made the wish that the staff would never be the property of anyone but always in the service of the world. He entrusted it to Érillion who became its guardian and was given the mission to travel around the world. For more than six centuries, Érillion traveled the world with the staff of Yresse and put it in the service of people.

Rather than using his powers himself, Érillion travels the world in search of wise individuals and entrusts them with the staff to continue his mission. Thus, from century to century, the stick has experienced several lives and is at the center of legends in many cultures.