Riddle of the Watcher (SOLVED)

Hey there! I've figured it has been awhile since my previous riddle was solved (got to 400 guesses), so why not put up a new one? [b]Here we go![/b] [i]I stand on watch, day and night You fight to protect my home as I watch You all fade away, yet return as I watch You've killed gods and kings as I watch You've become Legend as I watch Similar to a book, the one who watches Nine reasons I spiral in the cosmos as I watch Glowing of red and blue as I watch Forever imprinted as I watch[/i] [b]Go[url=http://postimg.org/image/qwc5lfydd/]o[/url]dluck all![/b] Answer: [spoiler]The purple symbol that appears in the Tower while Xur is present. Solved by hardsackboy.[/spoiler] [spoiler]Hint 1: [i]Without a true voice I thank you, silently waiting as I watch[/i][/spoiler] [spoiler]Hint 2: [i]I have no eyes, yet I see you every day as I watch[/i][/spoiler] [spoiler]Hint 3: [i]I am of three, yet you rarely notice me as I watch[/i][/spoiler] [spoiler]Final Hint: [i]Sparkling in the deep, unknown to most as I watch[/i][/spoiler] [spoiler]Final Final Hint: [i]I greet you immediately as I watch[/i][/spoiler] [spoiler] Final Final Final Hint: [i]Life is close to me, perfecting my trifecta of knowledge as I watch[/i][/spoiler] [spoiler]Final Final Final Final Hint: [i]I have faded from your sight, yet I still watch[/i][/spoiler] [spoiler]Final Final Final Final Final Hint: [i]My face lies inside the ring as I watch[/i][/spoiler] [spoiler]Final Final Final Final Final Final Hint: [i]I have long since been gone, few ever noticed my existence. Yet, I will always watch[/i][/spoiler] [spoiler]Final Final Final Final Final Final Final Hint: [i]I only appear when one of the Nine are here. That is when I watch[/i][/spoiler]