Known by the moniker Ar-Six, R6-H5 functioned as the astromech droid for the Jedi Master Kit Fisto. Throughout the Clone Wars, R6 was a constant presence, joining his master on numerous assignments within his Jedi starfighter.
After the Separatist leader, Viceroy Nute Gunray, orchestrated his escape from the Jedi Cruiser named Tranquility, R6-H5 accompanied his owner Kit Fisto in the pursuit of the Neimoidian. They tracked the signal emitted by a stolen Republic frigate's beacon, which led them to the third moon orbiting the planet Vassek situated in the Outer Rim. Upon arrival, they encountered Fisto's former apprentice, Nahdar Vebb, and Commander Fil's unit. R6-H5 remained behind with clone troopers Niner and Bel, guarding the ships positioned outside fortress. During this time, R6-H5 detected an incoming starfighter identified as belonging to General Grievous.
R6-H5 awaited further instructions from Fisto. However, after Niner and Bel met their death at the hands of Grievous's MagnaGuards, R6 was compelled to take flight and conceal himself within the fog to avoid capture. R6-H5 then established contact with Fisto, who directed R6 to the lower landing platform. R6 complied, successfully extracting Fisto from a confrontation with Grievous, and subsequently transported him back to Coruscant to deliver their report.
Following this incident, R6-H5 continued his service alongside Fisto throughout the Clone Wars, even accompanying him to Lola Sayu during a mission aimed at assisting Master Plo Koon in the rescue of Jedi Master Obi-Wan Kenobi's team from the Citadel, a Separatist prison.
R6-H5, standing at a height of 0.96 meters (3 feet and 2 inches), was an R-series astromech droid. As Kit Fisto's dedicated droid, he frequently expressed concern for his master's well-being, a trait Fisto found simultaneously endearing and somewhat bothersome. During the Mission to Vassek 3, R6 exhibited his anxiety by promptly informing Fisto of General Grievous's arrival in his starfighter and his impending approach towards the Jedi.
Being an astromech droid, R6 possessed the skills necessary for starfighter maintenance and repair, in addition to piloting capabilities. When the magnaguards had R6 trapped inside Fisto's starfighter, Fisto used his comlink and commanded R6 to pilot his fighter away from the magnaguards and later used his comlink to call R6 for pickup, so he could escape from Grievous.