Erethdor is the elf possessing Solak. He is encountered during the third phase when Merethiel sends the players to Solak's mind.
Erethdor attacks with ranged abilities, has 500,000 lifepoints in group mode and 250,000 lifepoints in duo mode, and players cannot use food to heal themselves while they battle him within Solak's mind. Erethdor will also force players out of Solak's mind after a set period of time. If Erethdor's lifepoints are brought to zero, the next phase automatically begins. Otherwise, all eight green circles summoned by Merethiel around the arena will need to be filled with corruption.
Erethdor was an elite elven warrior sent by Seren to aid Solak, along with Merethiel, Faerdhinen, and Saeldor. Merethiel describes him as distant, rarely showing his true feelings and having an insatiable desire for power and knowledge. They eventually stole a grimoire from the grand library of Prifddinas, which told of a form of magic later known to be blight. Merethiel describes it as extremely destructive, yet calm and yielding. As Erethdor learned more and mastered this magic, he became ever more power hungry, rarely interacting with his siblings and spending virtually all of his time scouring new scrolls. Merethiel later stole the grimoire hoping to learn about what Erethdor was doing, but crucial pages of it had been torn out.
He and his siblings were later tasked by Seren with helping Solak guard the Lost Grove. Here he would eventually learn of the heart of the tree, the grove's most powerful artefact which Solak guarded, and became set on taking its power for himself. He attacked Solak using the powerful blight magic he had learned, but ultimately was defeated by the joint effort of Solak and his siblings, splitting his mind and sealing half of it within Solak. Over time however, Erethdor's influence began corrupting Solak, prompting the guardian to seal off the Grove to protect Gielinor. He eventually gained complete control over Solak and became a serious threat to the world after the Lost Grove reappeared. However Merethiel, the World Guardian aand their allies confronted and severed his influence over Solak, though his current status is unknown due to his other half being contained in a stone by Merethiel.
- Erethdor is spelled "Eredthor" when interacting with The Lost Grove ruins.
- Erethdor's life points in duo mode were lowered to 250,000 on 18 June 2018. Previously, he had 500,000 life points in both modes.
- He is the original owner of the Blightbound crossbows, as he wields them in battle and the bows themselves are referred to as belonging to him in the server wide announcement which appears when a bow is received.