They would present characteristics from both sides of their heritage while being a unique being themselves. Despite their demonic abilities, some half-demons had no visible demonic traits and looked like ordinary humans, like Connor, Billy, and Cordelia. However, some half-demons still manifested some demonic traits that revealed their heritage, like Sara and Mal Fraser.
Even though some demons had a tendency to impregnate humans with their spawn or create new demons by infecting humans (Haxil beasts, Skilosh demons, and so on), the offspring wasn't a half-demon but rather from the species of their demonic parent, since these were simply cases of parasitism.
Half-demons did not form a separate society, they either allied themselves with humans or demons, depending on which species they felt they belonged to. However, Pearl and Nash were convinced that half-demons were an evolution of demons and humans alike. Humans looked at them as modern but weak, while demons considered them strong but archaic.
Humans and demons responded to half-demons in a range of different ways. The Scourge chased half-demons when they found them, while also considering common demons to be tainted with humanity. The Groosalugg in Pylea undertook very dangerous quests because his society saw his human appearance as a great shame. Billy's family feared him because of his powers and malice. Josh bullied his half-sister for being a half-demon.
By contrast, Angel and Cordelia did not have a problem with Doyle being a half-demon as his friends and colleagues at Angel Investigations. Also, Rieff's mother was accepted as a member by the Lister Clan, and Mal Fraser was the leader of the demons from the Fraser Gang.
The family of Tara Maclay claimed that the women in their family were partly demonic, a lie used to control and repress these women's witchcraft potential. Ruby Monahan's parents also lied when they told Spike that their daughter was a half-Sadecki demon imprisoned in the Mosaic Wellness Center, a story part of their plan to get revenge on him.
Powers and abilities
- Superhuman physiology: Half-demons demonstrated in fights that they were superior to a human in their strength, speed, stamina, reflexes, agility, and resistance. The exact extent of their power varied and depended on to which species of demons they were related. Half-demons could be stronger than vampires or compete with demons.
- Regeneration: Half-demons could heal themselves from injuries faster than humans. After his first fight against the Beast, Connor had a bruise on his chest that Jasmine assumed it was broken ribs, but it healed quickly. Groo was also injured when he fought a demonic tree, and Cordelia noticed that he was healing quickly, similar to Angel, a vampire over two hundred years old.
- Shapeshifting: Some half-demons had the ability to change from a human form to a demonic form. Doyle and Rieff's mother pretended to be human in order not to attract attention in human society. Transforming into demonic form made a half-demon much stronger, which was why Doyle, Whistler, and Mal Fraser would transform before a fight.
- Unique powers: A half-demon unique characteristics would vary in relation to their demon heritage. Billy could get men to kill, Nash and Pearl could fly and attack with energy beams, and Cordelia gained special abilities after her transformation into half-demon.
- Weaknesses: Apparently, the same mystical rules applied to half-demons as demons. Magical traps or dungeons that could hold a demon prisoner worked the same way with a half-demon. While the Hyperion Hotel was under a Sanctorium spell, which was designed to prevent violence by demons, Connor was surprised when he realized that this magic also warded off his attacks. Additionally, while vampires could not enter a human's home without an invitation, this did not apply to demons and half-demons by extension, so Angel was able to enter the homes of Billy and Connor without being invited.
Half-demons with their known origins and characteristics.
- William Blim — He was conceived when his human father raped his demon mother. He manifested the power to bring out the primal misogyny of any man who touched him or came into contact with his body fluids.
- Cordelia Chase — She was made part demon by the Powers That Be. With her new physiology, she gained the power to withstand the visions, levitate, and generate spiritual light.
- Connor — He was a unique being "impossibly" conceived by two vampires, who were a mixture of human and demon themselves. Being a natural born vampire, Connor was alive and not an undead being like all vampires. Nonetheless, he possessed a vampire's superhuman strength, speed, endurance, and healing factor; without any vampiric vulnerabilities, such as holy items, stakes, need to consume blood, or sunlight.
- Allen Francis Doyle — Born to a human mother and a Brachen demon father, he never knew his father or anyone on that side of his family. Doyle's demonic heritage didn't physically manifest themselves until he was 21 years old, and he didn't take the news well. He could shift from human to demonic appearance, which enhanced his abilities.
- Mal Fraser — He was a notorious crime boss from London. He was involved in many criminal activities, including magical artifacts. Even the Watchers Council knew about his activities. He was also the leader of the Fraser Gang.
- Groosalugg — He was born as a child of Pylean demons; however, he had a human ancestry that manifested in him as looking mostly human. As part human, he was considered unworthy and cast from his village. Cut off from his parents and forced to make his way on his own, Groo entered every contest of skill and daring in an attempt to die. However, he was always victorious, and thus he became known as "the brave — undefeated."
- Sara Harris — She existed in a vision as the biological daughter of Anya and an undisclosed demon. Despite her overall human appearance, Sara had notable long floppy ears and blue eyelids, about which her older brother teased her.
- Nash — He and his sister Pearl were born from one of their human mother's attempts to deliberately impregnate herself from a demon, as Susan Finney believed that half-demons represented the "next stage of evolution" of humans and demons alike.
- Pearl — She and her brother Nash were born from one of their human mother's attempts to deliberately impregnate herself from a demon, as Susan believed that half-demons represented the "next stage of evolution" of humans and demons alike.
- Rieff's mother — She was a member of the Lister Clan.
- Whistler — He was conceived by a pureblood demon with an agent of the Powers That Be. In response, demons and higher beings united to kill the couple for breaking the rules. Though the demons wanted to eat the child, the Powers protected and raised Whistler.
Behind the scenes
- Half-demons are seen much more often in Angel than in Buffy the Vampire Slayer.
- Known half-demons from dubious and non-canon are: Camazotz, Doug, Alexander Harris, Leo Silvera, Darrow Steele, the Dark Slayer (second attempt), and the Dark Slayer (third attempt).