The Light amidst the Darkness

The light that will eat out all the darkness in the world. Zoe, the most powerful light wizard in existence, is nearing her death. She's already over 10,000 years old and no man was able to capture her heart. The only partner she had was her cat. Her cat's name is Beru. Its color is black with a shade of emerald green. Its eyes are as hollow as the abyss. There's no pupil, no color at all. Looking at it will make you see the past and the future. Sitting in her chair made out of adamantium, the god mineral. She is reminiscing about her past. How she struggled from being an orphan, to being a slave and finally after being recognized having affinity with mana, she was saved and was taught about magic. Her breathing is getting rough. Her body is collapsing and her eyes are barely open. With her last breath, she uttered her last will to her precious cat. She said, "Find the most promising creature and impart to it all the knowledge that I have accumulated over 10 millennia." The cat did not respond, instead it only stared into her eyes. Zoe passed away with only one regret and that would be not experiencing what normal humans do, falling in love, having kids and growing old with someone she loves. Now that Zoe is gone. Beru is now the only one left inside the castle. The castle is located at the top of the tallest mountain in the north. With its harsh climate, having a temperature of minus 100 Fahrenheit (minus 100 celsius). There were countless adventurers who tried to explore the tallest mountain, hoping to encounter treasures. But what awaits them are the creatures hideous enough to scare the shit out of them. Those encounters with the monsters spread to all adventurers and no attempt was once again made to explore the North.