Kuwabara is Yusuke's best friend and former rival. He's not actually an official rei kai detective, he's only helping Yusuke accomplish his missions. He often challenges Yusuke to a fight eventhough he always end up unconsciously beaten down. Kuwabara is also brave and the bravest of all Yusuke's foes in his school. Actually, Kuwabara seems to be the second strongest person in their school. Yusuke just kept him second. He also has a lot of gangster foes who come from different schools. When Yusuke died, he came to his burial shouting that they both still have a score to settle so he shouldn't have died. He wept afterwards because ,somehow, Yusuke has been a part of his life.

Rei Kan - ability to feel spiritual phenomenon.
Kuwabara is often considered as weak and pathetic by Hiei, and by his own sister, Shizuru. But despite of being weak and being a clown in Urameshi's group, he is also a great advantage on their team because of his extraordinary rei kan capability. This ability of his was already introduced during the second episode. He felt a spirit roaming near him but he didn't know it was Yusuke's. He also told his friends who were with him at that time that the spirit was from a cat or a dog. Of course, Yusuke went mad. Anyway, he can sense danger when it's near and he can also speak directly through others' minds which are very essential to their team's success during battles.

His rei ken ( spiritual sword ) first appeared during his match with Musashi ( during the tournament of Genkai ). When Musashi attacked him with his wooden sword, Kuwabara counterattacked using his rei ki unvoluntarily. His rei ki was materialized as a sword since he was holding a small part of Musashi's sword that was broken.

Besides his capabilities in relation to his rei ki, he is also a man with a word of honor. He once had promised his friend ( locally dubbed as "Eric" ) that he would not fight his enemies in a week, if this was however not fulfilled, the school won't allow his friend to resume his part-time job. Kuwabara kept his promise eventhough alot of gangsters challenged him and beat him up. He also tried his best to pass the physical science test given to them by their villaneous teacher which he also gave his word that he would not fail. He tried his very best to pass it ( Yusuke's spirit also helped ) and so he and his friends did. After all these, Eric was allowed to have his part-time job. Yusuke was also impressed with the work that he had done to help Kuwabara.

And about his love life, he was inlove at first sight with Yukina at the moment he saw her on a video tape that Koenma gave them. Their mission was to rescue the Koorime maiden from an evil merchant. And because of Kuwabara's burning love with Yukina, they were successful in saving her.Though, it was unfortunate for Kuwabara that he is totally clueless about Yukina being Hiei's younger sister.