Arachnos was an ancient and powerful sorcerer was also known as 'The Life Stealer'.
It is certain that Arachnos was alive before the Great War against Chaos. Depending on the dates of Faleha's downfall it is likely that he was alive pre 1600 OT. Some have even suggested that it may even have been Arachnos who lead the enemies of the Stargazers before the Splitting of the Continents, and thus caused their downfall. Certainly he has been a most persistent and dedicated follower of the Demon Princes. Arachnos' final downfall came when he plotted to take control of Arion. His capture of the Princess Royal Telessa lead to the involvement of a great hero, known as the Lonely Mariner, who destroyed Arachnos beneath Deathmoor.