Good Characters:

 

Yuske: Fourteen-year-old Yusuke Urameshi is the worst student at Sarayashiki Junior High. He gets terrible grades, skips class as often as possible, and has little respect for authority.
On top of that, his coarse language and brash, arrogant manner get him into more altercations than he can count. Fortunately for him, he's good at protecting himself. Really good.
In fact, Yusuke has the reputation of being the toughest kid in town. But despite his killer rep, Yusuke is misunderstood. His home life is troubled.
He is constantly hounded by his teachers, by his mother, and by fellow students gunning for him... As such, Yusuke is generally pretty miserable.
Only after being assigned the job of Spiritual Detective does Yusuke truly begin to find his place in life.

 

Kuwabara: Kuwabara is Yusuke's chief rival at Sarayashiki Junior High. Like Yusuke, he isn't the greatest student, but he is an excellent fighter. Next to Yusuke he is a formidable adversary.
Kuwabara is driven by an unwavering desire to be the best. Adding comic relief to Yu Yu Hakusho, Kuwabara has an affinity for kittens.

 

Hiei: Hiei is a fire apparition whose true origins are unknown. He is a master swordsman, and his strength and speed are incredible. However, these are hardly his most fearsome abilities.
Typically kept concealed behind a bandanna on his forehead is the Jagan, a mysterious third eye that possesses magical properties. With it he can control weak-minded humans, send telepathic messages, and move objects telekinetically.
Hiei is fiercely independent, and his raw ambition drives him to pursue his own agenda at all times. Although he generally cares little for human life, and views others as mere obstacles in the pursuit of his own goals, Hiei strictly adheres to his own unique code of honor.
As such, he helps those who help him, and is fiercely loyal to those who have managed to earn his respect.

 

Kurama: Not actually a human, Kurama has lived for over 300 years and possesses the wisdom and knowledge one would expect of someone his age. He is generally soft-spoken, almost eerily calm, even in the face of great adversity.
But this calm exterior belies Kurama's incredible strength.
He is a powerful, ruthless warrior, with wisdom and experience. As such, he is a formidable opponent to all he battles.

 

Kayko: Kayko is Yusuke's closest (and at times, only) friend. She and Yusuke have known each other since they were little children, and although he would never admit it, she is probably the person that he cares most about in the world.
As such, Kayko has a unique ability to talk sense into Yusuke when he is being stubborn or unruly. Kayko is one of the leading students in her school. Intelligent, friendly, and outgoing, she is well-liked and respected by her peers.
She is confident, self-assured, and at times a bit head-strong. She is brave in the face of danger, and will not hesitate to put herself at risk in order to help a friend in need.

 

Genkai: Genkai, aging master of the Reidoha (or Spirit Wave) fighting technique, wishes to pass her knowledge to one worthy pupil before she dies. Yusuke is chosen to be that pupil, and he soon discovers Genkai's training to be the most difficult ordeal of his life.
Despite her advanced years, Genkai constantly amazes Yusuke with her ability to perform superhuman feats of strength and agility. Her wit is as finely honed as her technique, and she possesses the wisdom that comes from a life rich with experience.
Impossible to intimidate, she stares unflinchingly into the face of danger, ready to meet even the most daunting of challenges.

 

Botan: A messenger of the Spirit World, Botan serves as a guide to newly-departed spirits. She is friendly and often quite chipper, but when it comes to performing her duties she is all business.
After Yusuke is assigned the job of Spiritual Detective, Koenma assigns Botan to be his assistant. Her knowledge and experience often prove invaluable to Yusuke during his many adventures.

 

Koenma: Son of King Yama, ruler of the Spirit World, Koenma is left in charge of day to day operations while his father is away on vacation (a chore he despises - too much paperwork!).
Koenma's youthful appearance is quite deceiving - the little prince is actually over 700 years old! Koenma possesses the wisdom to accompany his years, and can pose a rather commanding figure in spite of his diminutive size.
There's only one thing that Koenma fears - making his father angry

Villains:

 

Bakken: Large and oafish, Bakken wears the scars of many battles. He takes advantage of an unconscious Kurama by attacking him while he is defenseless. Bakken's White Mist technique creates a cloud of mist from his body that allows him to attack unseen.

 

Byakko: The second of the Four Saint Beasts, Byakko is a ferocious white tiger whose imposing size and incredible strength cause even the most battle-hardened opponents to shake with fear.
Byakko is able to feed on the energy of his foes and uses the resulting boost in power to increase his size, create additional tiger beasts, and exercise his most dangerous attack - the Tiger Scream.

 

GameMaster: At only 11 years of age, Gamemaster does not appear to be a terrible threat. However, he can make any video game into reality. Any person in his territory must play by game rules, or they will be destroyed

 

Elder Toguro: If his younger brother has the brawn, the older, smaller Toguro certainly has the brains. He has the amazing ability to shift his internal organs around inside his body allowing him to survive even the most powerful assaults.
As long as his vital parts remain intact, this Toguro brother is virtually unbeatable.

 

Younger Toguro: The younger Toguro possesses the ability to increase his already considerable size at will, multiplying his strength by a hundred fold or more.
He is a man of few words, but his contempt for humanity is apparent in the scowl that dominates his stone-like exterior. Though he often uses his powers in the service of evil, Toguro is not without honor. He does not destroy without reason

 

Hope you liked this quick description on MOST of the Yu Yu Hakusho characters.

~More to come^_^~