Below is a Mary Sue Example. Essentially, this is how NOT to write a character.
M'ryS'u Raven-Hunter Nocturne Darcy Tristan Krystal (also known as Azure Wrath Fury Dealer) is the most gorgeous, most powerful being in existence. She is immortal and has lived since the beginning of the universe.
Raven-Hunter, although has lived for thousands of years, appears only age 18 because she is immortal and young forever. She is part vampire, elf, angel and human, and she is highly attractive without making any sort of effort, and everyone around her swoons at her. Her eyes are like a kaleidoscope, changing color to reflect her mood and hidden sorrow.
Raven-Hunter wears high heel leather and is dressed sleekly with the latest fashion. Although her clothes are often seen as impractical for fighting, they do not get in her way.
Raven-Hunter is often very clumsy and dreamy. She is often stubborn about things, but this has always helped her. She is highly charasmatic, able to turn the most evil of villains to good. Raven-Hunter frequently angsts about her past and about being immortal as well.
Raven-Hunter is a complete genius, having aced all of her classes. When it comes to mastering new skills, she is an instant expert. For example, she learned how to play a variety of musical instruments, getting each note right on her first try. She can speak 500 different languages, among them being Common Tongue, Xengese, Luuschtuntski, Russian, Spanish, French, Canadian and American. She learned these languages at an early age and can speak all of them fluently and flawlessly even better than some well-versed native speakers.
Since then, she is known by many to be a quick learner, able to pick up skills within minutes.
Raven-Hunter existed since the beginning of the universe and fought against the forces of evil. However, she was struck in the head and suffered amnesia. Until much later, she would not remember this glorious past.
Later, she was adopted by a poor farm family with two parents and several siblings. However, the great force of evil ravaged her home, burning her town down to the ground and she was the only survivor. She later attended school in another local village. She did so well in her classes that after graduating high school, she completed a PhD in only a month because she was just that good.
Afterwards, she later found out she had to play herrole as the Chosen Prophet of Ultimate Destiny for the Universe. It turns out she was the last of all vampire-elf-angel-humans and is also the last heir to become princess of Erudite.
As Raven-Hunter is the Chosen Prophet of Ultimate Destiny, she has powers beyond comprehension of mortals. She has unlimited magic abilities and can do anything. She can transform into a flying unicorn-chimera-dragon-spirit that can repels evil just at the sight of it.
Even when she is not in this ultimate form, she is immortal and cannot be killed. Even if she gets a single scratch, it heals instantly. Also, in the midst of battle, her makeup never gets damaged and she remains pretty and well groomed at all times.
Raven-Hunter shares all of my own personality traits and has the same personality quirks as I do. She also shares the same beliefs and principles as me. Anyone that criticizes my beloved Raven-Hunter is stupid and ignorant and doesn't know what they are talking about. They should know better that my character is always right and is better than yours.
The issue with this character is that it is not relatable. Characters such as these are distant and are more or less the fantasy version of the author. The Trivia section is obviously evident of this.
This character is also riddled with cliche after cliche. These ideas have been done before, and Raven-Hunter comes across as a pale imitation of more thoughtfully designed characters. It is in your best interest to avoid characters like this completely.