He's still an asshole, but at least he has one good thing about him, not that it helps his case.
In order to be a Complete Monster, you need to lack any altruistic quality, on top of being truly heinous by the standards of the story. The Borderline Monster, is what happens when you're every bit as heinous as a Complete Monster, but you have at least one good thing about you that keeps us from calling you Completely Monstrous. The Borderline Monster has to have someone that they genuinely care about. They may Freak Out once that person's dead, they may refrain from harming that person or they may care enough to apologize to that person just before committing an atrocity. However, that one act of kindness, however little, doesn't excuse all the other times that you Kick the Dog, and the story makes sure to continue portraying you in a negative light otherwise. If the Borderline Monster has a Morality Pet, that still won't mean the Borderline Monster won't cause harm to others anyway. If there's someone that the Borderline Monster does care for, the Borderline Monster still, evidently, doesn't care about them enough to help them, or tell them the truth about how cruel they really are to other people.
- Richard Detmer in Chronicle, who's a physically and psychological Abusive Parent to his son, Andrew. His mistreatment of his son eventually drove Andrew into a Roaring Rampage of Revenge. Richard was genuinely saddened when his wife died, but he still blamed his son for her death, and moved over to punch him while he was still recovering from the hospital.
- Nnoitra Gilga, who is bloodthirsty, had no problem attacking or killing his comrades, claims to be sexist, mass murdered many. However, he cared about his one fraccion-Tesla. The author labels Tesla as Nnoitra's "trusted confidant." When Tesla attacks Zaraki, Nnoitra thorws Orihime aside, and screams for him to run. Which is big considering Nnoitra doesn't back down from a fight, wants to die in battle, and thinks a warrior's death is honourable, and seems to hate weakness, but he wants his subordinate not to fight, and actively run. Kubo classifying in the databook that Nnoitra felt grief, when Tesla is cut down.
- Yammy Llargo, who mass-murdered hundreds of civilians, brutalized both his enemies and his allies, and butchered a nurse who had just reattached his arm. He's never physically harmed his literal Morality Pet, but that doesn't stop him from mistreating it anyway (throwing stuff at it and yelling at it to leave his sight).
- Shukuro Tsukishima, whose main power is Retconjuration, where he inserts himself into peoples' memory. He achieves this by stabbing people with his sword. He uses it on all of Ichigo's friends, including his pre-teen sisters, specifically to screw with Ichigo's head. With Sado and Inoue, he takes it a step further, by replacing the memory of Inoue's brother and Sado's grandfather with himself. When they start fighting his control, instead of just bringing them back under his influence, Tsukishima sends conflicting memories that mentally and physically tortured them. When called out on it by Ginjo, Tsukishima's response is a polite smile oozing with sadism, and it's implied that Tsukishima's deliberately broken other people for his amusement. His loyalty to Ginjo (evidenced by Tsukishima's Freak Out once Ginjo died) is just about his only good quality, and it does noting to excuse the torment he put Sado and Inoue through, as well as Ichigo to an extent.
- Kore is a Knight Templar who is perfectly willing to murder beings who pose no threat to him and carry out Cold-Blooded Torture if he thinks it will eradicate evil. He does however, make a point of apologizing to one of his first 'on-screen' victims, an orphaned child, telling him that because of his upbringing, he could grow up to have more sympathy for the 'monstrous races' that Kore has sworn to destroy and any evil, even the potential for greater evil in the future, must be mercilessly destroyed.
- Psion Minmax wants to completely destroy reality because he believes that nonexistence is preferable to the suffering things endure while they exist. He expresses regret over having to murder and resurrect one of his allies 817 times in order to bring about his goal, but that doesn't stop him from killing her for the 818th time.
Hello, Unknown Troper. You'll need to get known to lend a hand here.