Kyle Chutsky is a character in the Dexter Novels.
Featured as Deborah Morgan's boyfriend, he is a 40-ish former Black Ops assassin, who was retired from clandestine service due to injuries suffered on the job.
"Kyle Chutsky" is probably not his real name.
He is large, stocky, highly muscular, described in a way reminiscent of the spec ops team from Predator 1. He is covered in scars from various weapons for his time in clandestine ops.
Kyle is portrayed as somewhat cocky, prior to losing parts of his limbs at the hands of Dr. Danco. He is flamboyant, exaggerating his emotional responses to cover the icy coldness held underneath, from all his time as a black ops stone cold killer. After his dismemberment, he feels he isn't good enough for Debbie, as he is old and ineffective. His insecurity finally leads him to leave Debbie for her own good, as he's failed to protect her one last time.
He was first recruited into black ops, when he transferred to "The Dark Side" of Special Operations in El Salvador in the 1990s. There he formed a political kill team with several others, such as Dr. Danco, Albert Doakes, and others, as detailed in Dearly Devoted Dexter.
He shows up in the book series in Dearly Devoted Dexter when Dr. Danco mutilates a former comrade, and Doakes recognizes the handiwork. This gets Washington to send down Chutsky, who takes over the investigation. He and Debbie become a couple while working the case. When he's kidnapped by Dr. Danco, his little finger, complete with pinky ring, is cut off and sent to Debbie. Doakes, Debbie and Dexter work together to try to get him back. Dexter retrieves him from Dr. Danco's lair, short his left hand and right foot. He finally screws up his courage to go after Dr. Danco, rescuing Dexter when Dexter fails to get Dr. Danco, and also rescuing Doakes, from who Dr. Danco has removed both hands and both feet, as well as his tongue. In Dexter by Design, he gets a special doctor to fly in from Washington to help Debbie after she's stabbed. Then he helps Dexter try to kill the assailant, by flying him to Havana, and getting guns, and then trying to convince Dexter that they need to kill Debbie's assailant. Unfortunately, Brandon Weiss figures out that they are there, and they need to flee Cuba immediately.
In Dexter is Delicious, he is called in to back up Dexter and Debbie as they raid Buccaneerland and take out a The Coven of cannibals. Unfortunately Debbie confiscates their cellphones because she wants the collar herself. As it passes, Debbie surrenders, Dexter is forced to surrender, and Kyle is taken by Brian Moser. After Kyle recovers he sobs over Debbie's unconscious form. After Brian rescues the trio, he says to Dexter ("buddy" in his parlance) to tell Debbie that he loves her, and drives off into the sunset. Debbie says this is because Kyle thinks he failed to protect her and is just a useless cripple and should leave before he screws up her life anymore. This is just as Debbie becomes pregnant.
He has not had contact with anyone since, and may not be aware that he is a father.
Several different characters form different aspects of Chutsky in the TV series. Frank Lundy is the most obvious analogue, being also from Washington, sent for a serial crimes case, with a close relationship with Deb.