Carl Knute (also spelled Karl Knute), husband of Gilliam Knute, is the father of Appleseed's heroine and lead character, Deunan. Never depicted in the anime portions of the saga, he appears briefly as a silhouette in volume one of the manga, The Promethean Challenge, while a generic looking sketch of him is seen in the Appleseed Databook.
Little is known about Carl beyond the fact he was a talented operative of the LAPD SWAT, and later a high-ranking military commander. He toured in one, or both, of the world wars of the late twenty-first and early twenty-second century.
Carl also steers Deunan towards a career in the armed forces, only this time it's following the murder of her mother (who goes unnamed) by black supremacists in Los Angeles.
According to Nike, in Prometheus Unbound, he was offered guaranteed immigration clearance into Olympus, but rejected the offer for undisclosed reasons, and chose remain in Imperial Americana instead. While the manga fails to state his cause of death (or even admit he died, other than through repeated past tense references to him) the anime (at least in the Sentai dub) explains his death to be cancer related.
Prior to the murder of Gilliam by anti-Bioroid militants, he donated significant genetic profiles to the creation of the engineered human species, and his DNA resides in nearly every Bioroid created thereon. Afterwards, he obsessively steered his daughter Deunan towards a career with the LAPD's SWAT unit, and ultimately the armed forces of the United States, effectively crafting her into the protagonist of the series she became.
At one point in the first episode, Briareos is narrating part of Deunan's background. As he describes her father, he flashes back to what looks like an image of a very young Briareos (his hair is short) looking at a man with blonde hair and a moustache who is indicated to be Carl. This is the first clear image of him.
In the third episode, as Briareos is having another flashback of talking to Carl, a picture of a younger Carl with Deunan's mother holding Deunan as a baby is seen.