Dennisol was aboard the Umberfall when it received the call from Republic Communications Team Oh-Arr-Ee-Three-Six-One about EX-8C distress message. The ship landed on Aubadas and Dennisol joined the rest of the group as they explored the surface and tried to find the natives. As they traveled, the medic wondered if they were being setup for an trap, but Silandra Sho reassured him that they were safe. Dennisol's heavy long-range comlink picked up a faint signal from Amos Tillian as the communications team entered the atmosphere. He gave the coordinates to them so they could land close and join up with the Pathfinders. He informed his colleagues that something was interfering with communications and suggested they stay close together.
Dennisol and the rest of the Republic personnel were escorted by the Katikoot into their capital city Diurna and waited while the Jedi discussed the situation with the Kittik. Sho met them and explained the situation on Gloam and her plan to return to the planet to investigate. Dennisol agreed to join her and broke up a fight between the team's two droids, GT-11 and EX-9B.
After landing on Gloam, Dennisol had to attend to Rillik who had collapsed due to his afflication. The others made plans to explore the landscape while the medic moved Rillik to the ship's small sick bay and did some tests on his patient. He drew multiple blood samples from the Katikoot and was able to determine there was an almost parasitic relationship between the minerals of Gloam and the Katikoot species. The medic hypothesized that the minerals were alive like a fungus or disease and activated once it came in contact with Katikoot blood. He continued to do tests but was optimistic that a treatment could be found for the miner's curse. Dennisol left Rillik in the med bay and went to the common part of the ship to get something to eat. He was confronted by Rillik who knocked him unconscious with a metal strut from a cart.
Regaining consciousness, Dennisol realized he had dried blood on his head and was likely concussed. With the help of EX-9B, he was able to get free from the restraints that Rillik had used on him and came up with a plan to subdue the Katikoot. Pretending to still be tied up, he called for Rillik to come to him and asked him why he had attacked the medic. While Rillik was distracted by talking to Dennisol, EX-9B came up behind him and applied an electrical shock to Rillik and knocked him out. He tied him up and ordered the droid to try and reach the Jedi to warn them that Rillik had sent them into a trap. He was able to connect to Rooper Nitani due to the comms team fixing the sabotage on Aubadas. He told her why Rillik had sent the Pathfinder teams to be destroyed by the Gloam monsters and warned her that Mittik and Dietrix Jago were heading into danger by going to the ancient city. After the Jedi rescued the rest of the survivors on Gloam and collapsed the ancient city to seal in the monsters, Dennisol was contacted by Jago who told him to start up the engines of the Umberfall and prepare for a quick take off. The medic and the rest of the group returned to Aubadas. He was able to stabilize Rillik who had started to succumb to the miner's curse but was unable to heal him. His research did help others afflicted by the disease and many would make a full recovery. He accompanied the rest of the Pathfinders and the Leffbruks to Batuu where he took time to heal from the injuries he sustained on Gloam.
Dennisol usually wore the white and navy uniform of the Pathfinders.
- Star Wars: The High Republic Character Encyclopedia