what is significant about his eye?
The Eye was used as a symbol on armor and banners of Mordor, representing Sauron's quasi-omnipotence.
Sauron
Throughout "The Lord of the Rings", "the Eye" (the Red Eye, the Evil Eye, the Lidless Eye, the Great Eye) is the image most often associated with Sauron. Sauron's Orcs bore the symbol of the Eye on their helmets and shields, and referred to him as the "Eye" because he did not allow his name to be written or spoken, according to Aragorn. The Lord of the Nazgûl threatened Éowyn with torture before the "Lidless Eye" at the Battle of the Pelennor Fields. Frodo had a vision of the Eye in the Mirror of Galadriel:

how old was bilbo when he found the ring 60 years old. does he appear in any fictional work? The title character and protagonist of J. R. R. Tolkien's 1937 novel "The Hobbit", a supporting character in "The Lord of the Rings", and the fictional narrator of all Tolkien's Middle-earth writings. what is his role in these stories? Was a hobbit . who is the novelist mentioned here? English writer, poet, philologist, and academic. who are some of his ancestors? Michel Tolkien, Christianus Tolkien, Daniel Gottlieb Tolkien,  Benjamin Tolkien. did he fight in any war? No, He was a temporary second lieutenant any other titles written by him? "The Book of Lost Tales", the tale of Beren and Lúthien, "The Lays of Beleriand". what is the first one about? It is a collection of early stories by writer, which were complex fictional myths. when was it published? In 1984. who are the other characters in the first novel by the author previously mentioned? Dark Lord Sauron, Frodo, Sam, Merry and Pippin. does the first character mentioned here have any other names or titles given to him? Other dark lord figures are Sauron (of Tolkien's "Lord of the Rings") and Morgoth (of Tolkien's "The Silmarillion"), Ineluki the Storm King of Tad Williams's "Memory, Sorrow, and Thorn" and Lord Voldemort of Rowling's "Harry Potter" series. what did the body of the first evil lord mentioned here look like? He is depicted as a humanoid figure.
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Sauron [SEP] Eye of Sauron
The mists surrounding Barad-dûr are briefly withdrawn, and: This raises the question of whether an "Eye" was Sauron's actual manifestation, or whether he had a body beyond the Eye. Gollum (who was tortured by Sauron in person) tells Frodo that Sauron has, at least, a "Black Hand" with four fingers. The missing finger was cut off when Isildur took the Ring, and the finger was still missing when Sauron reappeared centuries later. Tolkien writes in "The Silmarillion" that "the Eye of Sauron the Terrible few could endure" even "before" his body was lost in the War of the Last Alliance.