Darth Arho, hailing from the human species, was a male figure who achieved notoriety as a Dark Lord of the Sith. Furthermore, he served as a Dark Councilor within the ranks of the reconstituted Sith Empire.
During the Cold War, this Sith Lord demonstrated extreme ruthlessness when he traveled to Ilum. His sole objective was the complete annihilation of his adversaries, namely the Jedi and the Republic. Although his time on the Dark Council was short, it was significant. He rose to the Dark Council following the death and treachery of Darth Baras. The actions taken by the Jedi Order against the Sith Emperor only intensified Darth Arho's determination to achieve the ultimate defeat of the Republic.
Darth Arho generally avoided the political maneuvers of his fellow Dark Councilors, and his aggressive nature was often exploited by them. While he proved his leadership abilities on Ilum, the Dark Council was critical of his "win at all costs" mentality. However, after the disastrous loss suffered by the Empire during the Battle of Corellia, this perception changed. The Dark Council selected Darth Arho to spearhead Operation Dark Ice, which would eventually become known as the Battle of Ilum.
The initial invasion resulted in substantial Imperial losses, as the forces of Grand Moff Ilyan Regus found it difficult to adapt to Ilum's challenging conditions. Regus requested assistance from the Dark Council. Under the joint command of Regus and Arho, the Empire began to make considerable progress. Admiral Shai and Jedi Master Jaric Kaedan were killed, and the Jedi Temple fell into Imperial hands.
At this point, Supreme Commander Rans called upon the Republic's most valiant warriors to defend Ilum. In an attempt to swiftly conclude the conflict, Darth Arho launched an attack on the Republic's headquarters, capturing the entire command staff, including the Supreme Commander. Victory seemed imminent for the Empire. However, unbeknownst to the Sith, Darth Malgus was secretly providing the Republic with information about their movements, with the intention of eliminating his primary rival, Darth Arho. The Republic heroes successfully freed Rans, but not before Arho's apprentice, Lord Loyat, was captured. Using the intelligence provided by Malgus, the Republic heroes were able to finally defeat Darth Arho.
Darth Arho possessed significant skill with a lightsaber and was a formidable user of the dark side of the Force. He could employ Force choke to restrain his adversaries, as well as Force drain to eliminate enemies or allies, using their energy to heal himself and enhance his own power.