You were a great wizard once, but your magic and even your memories have faded. You served the King once, centuries ago, but the King's throne sits crumbling in disrepair. He still sleeps, you had been told; and when he wakes, he will end all fear and longing. You would wake him, but it is not time. Deep, hollow circles hang below your eyes, and your skin, your body, once beautiful like the universe, has lost its virility, and has taken a mottled gray color. You are a desiccated corpse. You would scream, belt your throat out until you're sore, make the heart inside your chest pump — and you did, at first — but you haven't been alive for centuries. Your heart doesn't pump anymore.
You used to stand beside the throne and contemplate, but not a thought crosses through your mind anymore. Occasionally you'll come close to thinking, but what would have been a thought seeps out of you before it can develop, and all you experience anymore are faint inklings, impressions of impressions. What little magic you have left is all that's keeping you "alive", holding your body together. You've drained the Ring of all its magic. It was semi-sapient once, just like you, but now it's dead. What's left of you — whatever sapience you have left — it doesn't know what to do.
For centuries, you've stood by the throne. For the first few decades, the King's seneschal held court in the grand hall. You stood by the throne. He occasionally asked your advice, and you served him, but you had never loved him. You had only loved the King. Eventually, the Seneschal grew old, and guttered out like a candle flame, but you stood by the throne, in the height of your virility despite the years. The steward came next, and he as well held court for decades, but he was deposed by the Horde. The Horde tried to install their own Caliph, but he and his army fell to ash before you. So long as the King slept, you would not permit the throne to be desecrated. The Horde feared you, so they fled. You remained by the throne.
As the centuries passed, the world fell into chaos, and everyone died: the courtiers, the people, the servants. The King had remained asleep through it all, resting. Your memories have faded, but you still remember the rumble, and how the hold shook and trembled, threatening to fly apart. If it weren't for the magic holding it together, it might have. But that magic has now faded, and the hold has fallen to chaos and ruin, just like you, just like the Universe. Still, you stand by the throne, waiting for your King to arise from his slumber. Your robes are tattered, and you've aged beyond repair, and all the magic that's still left in the world couldn't bring you back to life — but that's inconsequential. Your power fades, but the King's power grows. The king you loved — can you still love? — will awaken one of these days.
Until then, you hold the Ring, contemplating it with what's left of you, and wait for his return.
(This is based off the king and the years, which I've been getting heavy inspiration from for weeks. Which is funny. The writeup is so old!.)