- "World domination. You make it sound so unattainable."
- ―Opal Koboi in The Opal Deception
Opal Koboi was a highly intelligent and passionate pixie in her youth. She came to hate her father, who wanted her to become a stereotypical house wife. She, however, desired a career in the LEP, and soon built her own engineering company, which quickly put her father out of business, causing him to have a nervous breakdown and go insane. Koboi soon invested in having him and her mother sent to an asylum named Cumulus House and visited monthly.
Her long-time nemesis was the centaur Foaly, who beat Opal and her revolutionary artificial wings with an iris-camera in a competition at college. Her company held an ongoing rivalry with his innovations. She had the most patents in the fairy world, but there was still one centaur who had more: Foaly.
During the Spelltropy plague, Koboi Labs found the cure to the disease : the brain fluid of the Silky Sifaka Lemur, and began selling it to the fairy public before the LEP demanded all of it to entirely destroy the pandemic. However, the same brain fluid was necessary in Koboi's secret concoction which would enable her to manipulate time and space, and allowing her to eliminate Foaly's competition. Opal had already absorbed the brain fluids of various other animals which had enhanced her IQ. The cure for the plague resulted in the extinction of the lemur save one, which Koboi was to steal from the Extinctionists, the leader of which she had mesmerized into doing her bidding. However, the Artemis Fowl from the future returned to save the same lemur (Jayjay) to save his mother. In a fit of rage, Koboi hunted down Fowl and returned to the future with him. During the travel, Artemis explained his plans to Opal and she agreed to help. This formed a complex time paradox, and did not affect the life of Opal Koboi in the series.
Koboi formed an alliance with disgruntled LEP lieutenant, Briar Cudgeon and the B'wa Kell Goblin Triad whom she and Cudgeon supplied with Softnose Lasers and batteries. Their plan was to supply the LEP with the power to invade Police Plaza and topple the goblin infestation then destroy them when they were of no further use and take over The Lower Elements. Unfortunately for Opal and Cudgeon, Julius Root, along with Artemis, Holly, and Butler, learned learned that she and Briar were behind the B'wa Kell rebellion. Flying into a rage after Artemis revealed that Cudgeon was plotting to kill her, she attacked him and in the ensuing struggle, he was thrown into a pipe of heating plasma.
After breaking out of the comatose state induced by Julius Root, she became increasingly insecure and began suffering from Narcissus syndrome, a syndrome where the sufferer has spent so long in his or her own company that he or she sees no one else as equal to them (Artemis wrote an article on it himself under the pseudonym 'Sir. E Brum' (cerebrum)). Fowl's concoction made from the brain fluids of the Sifaka Lemur was able to cure this malady.
It is implied that Opal is in fact smarter than Artemis as in The Opal Deception it is stated that she has an IQ of over 300 while the highest human IQ ever recorded is 228. It is highly possible however that Artemis possesses a superhuman intellect. It could also be that the fairy IQ scale is different from our own.
Opal shared many of Artemis's traits. Both are young geniuses who have an antagonistic relationship with a rival species and both are especially concerned with money and power though much more so in Artemis's case. She could be thought of as a female, pixie mirror image of Artemis himself.
Opal loved chocolate truffles, keeping them in the hidden compartment, or "booty box", of her shuttle in The Opal Deception.
Opal's most well known ability was her genius intellect, which was rivaled only by Foaly, Minerva Paradizo, and Artemis Fowl. She created spectacular inventions using her intellect and earned her fortune with them (such as the Koboi DoubleDex wings). She also had her magical powers enhanced using the fluids of endangered animals. With her enhanced powers, she could use a more powerful version of the mesmer, levitate, shape-shift, suck out the memories of other people, had enhanced strength, powerful healing magic, summon energy beams that could paralyze creatures, and conjure up lightning bolts and spheres of fire. However, her intellect brings with it mental problems, such as schizophrenia. She was also a pathological liar.
With statements such as "before her second birthday she had dismantled her first hard drive," the Opal Koboi character comes off as precocious, but not in a positive way. Described as an "insane, power-mad pixie" and an outrageous character that is confident of her own intelligence in a way that annoys other people, this beauteous "pixie with the golden touch" contributes to the Colfer idea that fairies are basically as bad as us -and fight even dirtier. The name Koboi sounds both as "cowboy" and "kobold", a temperamental sprite of German folklore who becomes outraged when not fed properly, and who sometimes is referred to as a spirit of caves and mines, which fits since the fairies of the series live underground. In this way, the name Koboi suits the gold-digger Opal Koboi. It is also known that Koboi bankrupted her father's business after he tried to dissuade her from studying engineering (as he expected his daughter to follow the normal path in life for female pixies: namely, getting married to a suitable husband) and that she has a long, bitter rivalry with Foaly since their days at university, and that one of Opal's main goals is to prove she is intellectually superior to the centaur. The only reason to this hatred between the two magical creatures is that Foaly won their University's science fair with his iris-cam, which Opal found stupid and to which she thought that her Koboi wings were far superior. She then accuses the centaur of winning only because he was a male.
Opal's appearance is not described thoroughly at any one point in the books. However, at various points in passing in The Opal Deception, it is stated that she is extremely beautiful, has long black hair, chocolate-brown eyes, and 'porcelain' skin. As a pixie, she is roughly the size of a human child, with childlike proportions, including a comparatively large head. Artemis notes the second time he meets her, the first time after the mindwipe, that if he didn't know otherwise "he never would have guessed that the female before him was anything but a human child." Yet, the comparison to a human child is made invalid by the cover of the fourth book (The Opal Deception) since she is shown to have breasts. She could however have simply hid her breasts in some way while posing as a child.
The Arctic Incident graphic novel depicts her with dark red hair and dark red eyes, which either have no visible sclera (whites), or sclera identical in colour to the iris.
- "My truffles?... You took them. That's just mean."
- ―After attempting to kill Artemis and co.[src]
- "This is not a lemur."
- ―Opal Koboi, pointing at Artemis[src]
- "I see now, wing commander, that you never had any intention of sending the transfer shuttle right over. In fact, you were being sarcastic. Mocking me from the safety of Police Plaza in Haven. I waited for three weeks before I realized that the shuttle was not coming for me. I packed my belongings so that I would be ready. Including my collection of model sea horses, which I fashioned from chewed cardboard. My favorite sea horses, Twinky and Goodboy were broken in the process. Twinky cries every night over her severed tail and Goodboy does not look so dashing without his head. Your callousness leaves me no alternative but to place you in my revenge list. When I am finally free of this horrible place and elevated to my rightful position as queen of the world, you will take my place in this cell and I will send my troll minions to issue daily beatings with batons fashioned from sea horses' tails. A fitting punishment, I am sure you agree."
- ―Opal Koboi to Wing Commander Vinyaya
- "No, I will not kill Foaly just yet. Twice in my life I was beaten, both times it was Foaly. I want him beaten, humiliated and alone...and then I will kill him!"
- ―Opal Koboi in The Opal Deception
- When Artemis encountered Opal in the past in Artemis Fowl and the Time Paradox, she had gained awesome powers from ingesting various animal products and body parts, and yet the Opal he fought in Artemis Fowl and the Arctic Incident and Artemis Fowl and the Opal Deception did not. How she lost these powers and how her journey to the future in TTP effects the Opal in the present day is yet to be revealed. However, it is most likely that the magic enhancement was temporary, as she retained the animals even after they had served her purposes, suggesting that she requires a constant supply.
- It seems that the Opal from Artemis' past was somehow teleported back in time as of she is in her own future, the goblin revolution and the plots in the other books in the series would not happen. This, in fact, did not happen, with her younger self murdered on Opal's orders. Opal herself theorized that the timeline may have split, allowing this to happen.
- This may be just coincidental, but Opal Koboi seems to be at least one of the primary antagonists in every two books (2,4,6,8).
- Opal's death was very similar to another Eoin Colfer antagonist named Albert Garrick. Both were tricked by the main character, then declared their murderous intentions, causing them to be killed by one of their own henchmen.