Details: Keith was murdered before he even knew of her existence. But it was the spirit of Keith that help Karen carry and give birth to Lily. Throughout her life Lily always thought of her father and enough dreamed of him and questioned his death but overall had a very deep love of him.
Details: The two brothers had never been close growing up and into their adult years as Dan saw himself being superior to Keith due to his money and success, but despite this, harbored jealousy towards Keith for starting a life with Karen and Lucas and being the brother everyone liked more. Keith cared deeply about his younger brother. This all changed however, after Dan walked in on Deb and Keith sleeping together as Keith was depressed from having Karen reject his marriage proposal. Dan became determined to hurt his brother, hiring a woman named Jules to make Keith fall in love with her and then break his heart, which she did indirectly after walking out on him at the altar. During the school shooting, Dan shoots and kills Keith, mistakenly believing Keith tried to kill him in the dealership fire as payback for his revenge scheme with Jules. Keith's death left Dan guilt-ridden after learning that Deb was the one responsible for the attempted murder.
Details: Keith had become the closest thing that Lucas had as a father growing up and during his teen years. Lucas even lived with Keith for a short time when the two moved to Charleston. Although their relationship became strained upon Keith's discovery that Lucas knew about Dan paying Jules to break Keith's heart, upon his return to town, he, Karen and Lucas became close once again and he even planned on adopting Lucas as his son after becoming engaged to Karen. This never happened as Keith was shot and killed by Dan during the school shooting as Dan mistakenly believe Keith tried to kill him in the dealership fire. Keith's death affected Lucas deeply and motivated him to discover the truth behind the murder after seeing Keith in his coma dream.
Details: Due to Dan and Keith's rocky relationship Nathan and Keith didn't have a very strong relationship although Keith tried to protect Nathan from Dan. And while Dan was in hospital, Keith gave Nathan a job at Dan Scott Motors and together they built a car for Nathan's family. When Keith died Nathan was devastated but wished they had be closer.
Details: Keith had known Haley since she was young due to Haley being a close part of Keith's family with Karen and Lucas so she would often see him and interact with him at Karen's Cafe and other events and the two got on well. Haley was thrilled when Karen and Keith got together having seen the attraction before. Haley was deeply sadden by Keith's death and helped Karen through it.
Details: Keith was aware of Lucas' long-time crush on Peyton and would often tease him about it when they worked in the garage together. It was through Keith that Lucas had his fateful first conversation with Peyton, as Keith sent him on that service call when her car broke down. Though they were rarely (if ever) shown interacting, it is presumed they became friends due to her friendships with Lucas and Karen. She was thrilled to learn of his engagement to Karen. He saved her life during the school shooting, helping to convince Jimmy Edwards to let Lucas carry her outside to get medical attention, She was upset by his passing but was unable to attend his funeral due to being in the hospital. But she did make it to the wake. When she and Lucas got engaged she insisted on wearing Keith's ring, knowing how important it was to him.