Tanarus Aronn was a Dark Jedi.
Tanarus Aronn grew up an outcast because of his connection to the force. He lived in a village that considered the force to be a form of dark magic. Because of his skill with the force, the villagers thought he was evil. In order to redeem himself, he only used the force to help people, but the more he used the force, the more the village hated him, until he was eventually banished. Because he couldn't return home, he decided that he would become a Jedi and earn back his people's trust. After making his way to the Jedi Academy, it was discovered that while his skill with the force was enough to become a Jedi, his physical abilities were sub-standard. Because of this, he was accepted as a padawan on a trial basis and would only gain full acceptance when his physical skills matched his force skills. After years of training, he finally became strong enough to be a Jedi.
After gaining full acceptance into the Jedi, he went back to his village to try and be allowed back into the village. After he told his village that he joined the Jedi, Tanarus was surprised to see that they hated him more than ever. The leader of his village declared that he be imprisoned and his family be executed for creating him. After a year in prison, he planned to escape. Unfortunately, due to his physical weakness, his escape was doomed to fail. His escape attempt resulted in Tanarus losing both arms and being beaten nearly to death. He then began wondering if what if the people in his village were right and the force truly was evil. This, combined with the rage he felt from being hated by his own people despite being a Jedi, pushed him to the dark side. He managed to use the force to make the prison guards release him.
Tanarus eventually made his way to Darth Sidious and begged him to make him his apprentice. Darth Sidious refused to let him be his apprentice, stating that a Sith doesn't beg and that in his weakened state, he was of no use to him. He did, however, offer to replace his severed body parts. In addition to replacing his arms and his eye, he also added several implants to increase what little physical ability he had to the level of a Jedi Knight. Tanarus then decided that he truly was meant to be a Sith and set his sights on becoming a Dark Lord. After learning that Tanarus had abandoned the Jedi, his master decided to track him down and bring him back to the Jedi, one way or another. After finally locating him, he was surprised to see that Tanarus was stronger than his master ever was, even able to use a saberstaff and a shoto simultaneously. After a fierce battle, Tanarus emerged victorious. When asked why he had become a Sith, Tanarus stated that he had finally become the warrior he was born to be. His master told him that he hadn't become a great warrior, he just proved that his village was right about him being evil. Tanarus then remembered that he had always wanted his village to accept him, but instead he gave them more reasons to hate him. After finally seeing the error of his ways, Tanarus was invited to rejoin the Jedi. Tanarus accepted the invitation, but insisted that he be demoted to padawan until he redeemed himself.
Powers and abilities
When Tanarus first became a padawan, he was originally only accepted on a trial basis. While he had skill with the force, he had very little physical skill and as such, had very little skill in combat. He never reached his full potential until receiving various implants from the Sith and having his arms replaced with cybernetic ones. He eventually became skilled enough to use a double-bladed lightsaber and a shoto simultaneously.
After being nearly killed in prison, Tanarus lost both of his arms below the elbow. They were replaced with superior prosthetic ones by Darth Sidious. His prosthetic arms allowed him to use a double bladed lightsaber and a shoto simultaneously, which is amazing considering he could barely use a single lightsaber before receiving them.
Tanarus also received an unknown amount of implants that increased his meager skills to the level of a Jedi Knight.
During his time as a Sith, Tanarus built and used three lightsabers. Two were identical and could connect to form a saberstaff. His third lightsaber was a shoto with a curved hilt.