Visas Marr Speculation.

A sith scout for Darth Nihilus. Visas Marr was forced to travel through several worlds to find her master's enemies. Like the Jedi Exile for example. I believe that through this Visas honed her tracking skills and was well versed the art of stealth. Having been chosen as Darth Nihilus' sole apprentice out of the entire Sith remnant force would suggest that Visas was exceptionally strong in the Force and somehow impressed Nihilus.

Having trained under Nihilus as a Dark Jedi/Sith Sentinel. Visas would not doubt be well rounded in her skill set, combining both the lessons of the Force and those combat and learning them equally. This path would also allow Visas to hone her other skills,which could have been stealth, computer slicing or even repair. Having been trained as a Sentinel, I believe that one of Visas' more impressive skills were those that had much to do with guile and stealth, as she is shown to have infiltrated the Ebon Hawk without alerting Kreia, Atton Rand, Bao Dur, T3-M4, Brianna(an echani force sensitive) and Bao-Dur's remote droid. This would suggest that she possessed great talent with stealth and the Force concealment ability. As per her other abilities I would say that Visas was able to somehow use the Force to blind and/or throw her opponent off guard by making them only see through the force(something she did in cut-content)I would also say that because of her training under of Darth Nihilus, she would most likely have learned common dark side powers like Force Choke and to a lesser extent drain. she would no doubt also be capable of the usual force augmentation and Telekinesis.

As for her fighting style. I conclude that her style was either very rudimentary or severely lacking due to her training under Nihilus. And that her style matured as she returned to the Light side of the force. That said, i believe that Visas most likely trained in Shii-Cho and possessed some modicum of talent with Niman due to the Sentinel's focus on balance. However as i said before, this would be at a very rudimentary level until after her return to the lightside and training under Meetra Surik.

Due to source material and the Kotor 2 video game. I would say that Visas used a single hilt as her weapon of choice and gradually began to learn more of the blade under the Exile. She would also seem to possess some talent with Blasters as shown in source material, though to what extent is unknown.