Delak Krennel, a male Human originating from Corulag, was native to that planet. He would eventually enroll in the Imperial Navy of the Galactic Empire. Known for his aggressive command style, Krennel harbored a strong Humanocentric viewpoint, expressing animosity towards Non-humans.
Rising to the rank of Admiral, Krennel took command of the Imperial II-class Star Destroyer named Reckoning. He was then assigned to Grand Admiral Thrawn's fleet within the Unknown Regions. Disobeying direct orders out of hatred for Thrawn, Krennel launched merciless attacks against the enemy. Consequently, Thrawn severed Krennel's arm, which was then replaced with a prosthetic arm. Further punishment was intended on Coruscant, but the loss at Endor prevented this.
Subsequently, Krennel served Imperial Intelligence Director Ysanne Isard, who tasked him with eliminating former Grand Vizier Pestage, who had been ousted as Emperor. After killing Pestage, Krennel became a warlord, adopting the title "Prince-Admiral." and governing the Ciutric Hegemony. He provided financial support to Thrawn upon his return from the Unknown Regions to fight the New Republic. Later, seeking peace, Krennel permitted refugees into his territory. However, when the New Republic recovered plans suggesting he was building a Death Star-weapon, New Republic forces intervened to end Krennel's rule. Krennel met his demise in battle aboard the Reckoning, bringing an end to both his life and his faction.
Corulag was the planet where Krennel was born. From a young age, he displayed a strong Humanocentric attitude, along with a sadistic and brutal nature that would define his later years. This was evident when he aided his father in burning down alien-owned farmlands, allowing a Human agro-combine to seize the land.
His Imperial service began with his enrollment in the Prefsbelt IV Naval Academy. His academy record highlighted his success as an intramural unarmed combat champion. Even in his later years, Krennel maintained his fighting condition, further enhanced by a mechanical prosthetic replacing his right hand and forearm. This prosthetic was constructed of metal and emitted a red glow from within.
Following his graduation, Krennel was assigned to active duty under Grand Admiral Rufaan Tigellinus. Tigellinus, a refined commander, found Krennel's brutality distasteful and reassigned him to the Unknown Regions of the galaxy, where he served under the Chiss officer Thrawn. As a captain, he commanded the Star Destroyer Reckoning. Krennel resented serving under a nonhuman officer and being stationed in the Unknown Regions. Unable to express his frustration to Thrawn, he instead channeled his rage by intensifying his brutal treatment of alien prisoners. Eventually, Krennel's animosity towards Thrawn led him to use a force pike against one of Thrawn's artworks, mocking his superior's strategy of using alien art to exploit a race's weaknesses in battle. In response, Thrawn ordered one of his Noghri Death Commandos to sever Krennel's arm from the elbow down before he could inflict damage. Following this incident, Krennel gained a newfound respect for Thrawn and the power of fear, along with his prosthetic limb.
After the Battle of Endor, Krennel was promoted to the admiral rank. Under the orders of Ysanne Isard, the director of Imperial Intelligence, he piloted the Reckoning to planet Axxila in an attempt to capture an Alliance force led by Leia Organa. Krennel instructed his TIE/LN starfighter squadron to fire on local civilians to provoke the rebels, but he was forced to retreat empty-handed due to an AT3 Directive issued by Imperial defector Soontir Fel, who was posing as an undercover operative. Following Sate Pestage's insistence, Krennel complied, while also allowing a freighter piloted by pirate Captain Leonia Tavira to jump to lightspeed. Unbeknownst to the admiral, Pestage had made deals with both Tavira and the rebels to gain their support in his own defection. Pestage fled Coruscant for Ciutric IV, and Krennel, aligned with General Paltr Carvin of the tribunal that replaced the regent, was assigned to a retrieval mission on Ciutric, eager to atone for his deception at Axxila. While reviewing a tactical hologram for the coming operation, the admiral was intercepted by Isard, who negotiated possession of Pestage in exchange for political power and the addition of the Interdictor-class Star Destroyer Binder to Krennel's own Reckoning.
When Pestage escaped the New Republic, he sought refuge with Krennel, unaware of the admiral's hatred for him. Krennel strangled Pestage and seized his holdings in the Ciutric Hegemony, and then coldly murdered Pestage's entire family. Following this, Krennel proclaimed himself a warlord, taking the title of "Prince-Admiral."
During Thrawn's campaign, Krennel offered financial assistance and feigned obedience to his former commander's call for unity. In 9 ABY, following Thrawn's defeat at Bilbringi, Krennel was targeted to serve as an example of the New Republic's newly strengthened policy against warlords.
Working with the clone Isard, Krennel initiated a plan to create chaos within the New Republic by exploiting tensions between human and nonhuman species. This included disrupting freight traffic to Coruscant at Liinade III and ultimately conquering Coruscant. Rogue Squadron, with assistance from the original Ysanne Isard, quickly thwarted these plans. Wedge Antilles passed intelligence provided by Isard to the New Republic Defense Fleet, which dispatched a flotilla to Ciutric before Krennel's forces could launch their attack. The flotilla, under the command of Admiral Gial Ackbar, crushed Krennel's forces using a Thrawn Pincer and seized the shield-stripped capital of the Hegemony. Krennel perished aboard his flagship, the Reckoning, when a concussion missile fired from either the Selonian Fire or Corusca Fire penetrated the forward viewport. The impact shattered the viewport, sending shards of transparisteel through Krennel's body. The subsequent explosion destroyed Krennel and the entire bridge.
Krennel was a capable tactician and strategist, as evidenced by his promotion to Imperial Admiral. However, his inherently brutal nature made him less tolerant of the more subtle approaches favored by his former superiors, Thrawn and Isard. His typical response to any obstacle was to simply crush it.
He was highly sadistic and also exhibited masochistic tendencies, the latter developing after Thrawn removed his arm for attempting to damage one of his artworks.
During his brief period under the tutelage of Isard's clone as the ruler of the Ciutric Hegemony, he began experimenting with political propaganda and other methods of manipulating public opinion in his favor. He presented himself as a sympathetic ruler rather than a tyrant. He began to recognize the effectiveness of these methods and believed he was a quick learner who would soon master them without "Isard's" help. His death in battle, however, ended any potential he might have shown.