Creation
Nikki was created by writer John Ney Rieber and artist Peter Snejbjerg in The Books of Magic issue 5 in 1994.
Major Story Arcs
Summonings
Nikki, a continuously happy, innocent child, was born out of an affair between her human mother, Khara, and the archangel Araquel. Due to the illicit nature of the affair, Araquel chains himself over a pit as punishment, and Nikki rarely sees him.
Khara and Nikki tell him they are leaving for London, to stop Sir Timothy Hunter.
Khara and Nikki go to London and see Bill Hunter sitting inconsolately in his wrecked car, thinking of his dead wife. Khara reaches through the window and takes the photo of Mary Hunter out of his hands. She brings Bill back into his house to sleep it off. Nikki, meanwhile, shrinks the photo down to a few inches.
They find Sir Timothy Hunter, who is snooping on Tim Hunter. Khara throws the photo towards him and he catches it, and the literal weight of the memories drags him down to the ground. Khara says she likes Tim and warns Sir Timothy to stay away.
Later, Tim is being humorously chased by two girl friends of his, Molly and Marya. He can’t handle it, and accidentally freezes time. Khara and Nikki, however, are unfrozen, and chat with him. Partly Khara just wants him to learn to relax, love, and live with his magic. She also lends him 200 quid, because he’s broke and can’t afford ice cream with the girls. Nikki takes his magic Stone of Opening, which he got from Tam Lin in the Arcana Annual, as collateral. Khara says he’s better off without it for now, as it makes him release his power whenever he has high emotions, and he needs to plan more.
She also says that Nikki woke up his father from the coma he was in due to magical burns. Then she leaves Tim to figure out how to release Molly and Marya from his spell, which he does.
Reckonings
Later, she and Nikki sit after watching a musical act (seemingly Tori Amos). They go to swing in a playground, but are chased by some demons who look like pink Tyrannosaurs. Khara and Nikki hide from them by creating an illusion that they are trash cans. The Tyrannosaurs don’t see through the illusion but the demon Barbatos does, and has them grab them.
Barbatos then has Sir Timothy, who is under his spell, interrogate them. He believes they are in a palace but they are really in a cardboard box in an alley.
Khara manages to turn them back into their normal shape, but they’re magically chained. She accidentally drops the Stone of Opening, and Sir Timothy picks it up. It wakes him up out of the illusions Barbatos has placed on him. He releases Khara and Nikki and walks away, keeping the Stone.
However, she and Nikki go with him to her apartment. Sir Timothy apparently gives her the stone back. After Sir Timothy turns into a dragon, he tells Araquel where they are. Khara is still waiting to continue their affair.
Slave of Heavens
Much later, they are all living together happily. However, there is a war going on between angels and demons. They want Araquel to join but he refuses. However, he knows he needs to do something and leaves, leaving a note with Nikki to give to Khara.
Powers and Abilities
Nikki has various superhuman abilities, such as the ability to shrink a framed photo down to a much smaller size and the ability to create illusions. Khara says Nikki is good at waking up people and objects, as she did when Tim’s father was in a coma from magical burns.
Nikki’s powers presumably derive from her half-angel heritage, although her human mother Khara also has similar magical powers.