Castor (pronounced 'kăst·ûr) is a direct descendant of Eller, one of the First 50 Elves, who was himself the first Elf Chief and the third High Sorcerer. As is the case with most elves, Castor's surname is derived from his ancestry (the custom of adopting surnames was begun among elves long before the law which required humans to choose surnames). In 893, Castor became the third elf to be both Elf Chief and High Sorcerer, and the first to attain these titles simultaneously. This was because that was the year that the previous Elf Chief, Trent, and the High Sorcerer, Circe (who were husband and wife) retired together.
Castor was secretly contacted by Durell of Sorret in 901, and invited to take part in the Coming of the Order, which had begun in 897. However, just as it would be some time before most people were even aware of the Coming, it would not be until 31 Su'yet, 903, at the surprise attack later dubbed the Battle of Elves' Ambush, that anyone other than Durell and his allies in The Order became aware of this contact. There are any number of reasons Castor chose to join the Planners (as those behind the Coming are sometimes called), most importantly the fact that Durell and Arch-bishop Talak offered to lift the elves' banishment, and allow them to return to human society, if they helped win the impending war (which began about two years after Durell contacted Castor, and little over two months before the elves joined the war). It is also said that Castor had always found the title of "Elf Chief" somewhat ridiculous, and preferred the idea that after establishing the Second Order, he might be elected with the new title of "Chief Councillor". He is also known to have been strongly opposed to crime, and appreciated the establishment of InterVil, which Planners had suggested as a response to growing gang activity in human villages.