Xanatos was born in Bar Harbor, Maine, in 1955, the son of Petros Xanatos, a local fisherman. In 1975, he received a rare 10th century coin from a mysterious stranger (actually a member of the Illuminati Society), which he sold to a collector for 20,000 dollars. Xanatos then used that money to found Xanatos Enterprises, increasing his wealth until now he has become one of the richest men in the world. Along the way, he became a member of the Illuminati (currently a lower-echelon member).
In the course of time, Xanatos came into contact with Halcyon Renard, the CEO of Cyberbiotics. He and Renard quickly became determined rivals, particularly after Xanatos lured away two of Renard’s most talented employees, Owen Burnett and Anton Sevarius. Also around this time, Xanatos and Renard’s daughter Janine Renard a.k.a. Fox met, and became attracted to each other.
Not long after Owen entered Xanatos’s service, becoming his right-hand-man, he revealed his true identity to the billionaire as Puck, and offered him a choice between a single wish from Puck, or a lifetime of service from Owen. Xanatos chose Owen, and Owen has served him very capably ever since.
At some point between 1975 and 1994, Xanatos obtained the Grimorum Arcanorum from Mary and Finella. The two women also, with Brooklyn, arranged for him to meet Demona, Owen/Puck introducing the two to each other. Demona informed Xanatos about Goliath and his clan at Castle Wyvern, and he decided to awaken them, hoping that they could prove useful for many of his less-legal enterprises. Buying Castle Wyvern, he relocated it from the Scottish coast to the top of the Eyrie Building in New York, his personal headquarters, thus awakening the gargoyles. Next, he tricked the clan into believing that he had been robbed of three valuable computer disks from Cyberbiotics and asked them to recover them from him; in fact, the computer disks were Cyberbiotics property, which Xanatos hoped to obtain for himself. Using the information on the disks, he created the Steel Clan robots, which he intended as replacements for the gargoyles in case they turned out to be less easy to control than he had hoped. However, Elisa Maza alerted Goliath to what was actually going on, and in the ensuing melee, Goliath and his clan defeated the Steel Clan. Xanatos was afterwards arrested and sent to prison for receiving stolen property, for a few months’ time.
He quickly got out of prison, however, thanks to good lawyers, and returned to Castle Wyvern. While making a few efforts to recapture the gargoyles, he was now aware of the fact that bending them to his will would not be easily accomplished. And since the Steel Clan had not lived up to his expectations, he embarked on other schemes to create his own gargoyles. The first of these was by mutating four humans, including Maggie Reed and Elisa’s own brother Derek, into gargoyle-like creatures; this plan failed, however, when the Mutates decided to go their own way, and live in the Labyrinth as allies to Goliath and his clan. The second was when he had Goliath cloned, producing Thailog; this scheme miscarried also, even more alarmingly, for Thailog learned from Xanatos too well, promptly robbed him of 20 million dollars, and went off on his way as a future rival.
During this time, Xanatos and Fox remet, and finally became first engaged, then married outright. The gargoyles became involved when the Eye of Odin, which Xanatos had given Fox as an engagement gift, turned her into a werefox, and began to endanger her very life; Goliath came to Xanatos’s aid, and wrested the Eye from Fox, saving her. Xanatos invited Goliath to his wedding shortly afterwards, for the purpose of tricking him into supplying his half of the Phoenix Gate alongside Demona’s; he then used the Gate to travel back in time with Fox, Petros, Goliath, and Demona to Scotland in the year 975. There, Xanatos rescued Princess Elena from the Archmage’s bandits, in return for which a grateful Prince Malcolm gave him a few coins. One of these Xanatos sent to the Illuminati Society with instructions to deliver it to his younger self in 1975, hence setting up the foundations for his future wealth.
Xanatos and Goliath became allies once more, in earnest, when Demona cursed New York so that the bulk of its humans would turn to stone at night (this incident bringing his alliance with her to an end, along the way). Working together, they managed to break the spell. The truce was only temporary, however, for Xanatos continued to make other moves against the gargoyles, among them sending the upgraded Pack after the clan, kidnapping Hudson to use as a guinea pig for the Cauldron of Life, and even using Goliath and Angela for Coyote-bait in Arizona.
The real end of the war between Goliath and Xanatos came when Xanatos’s son Alexander was born, and Oberon and Titania decided to take the child away to Avalon. Xanatos and the clan joined forces in battling Oberon, although they (even with help from Halcyon Renard and Puck) were defeated in the end. But Goliath offered the compromise of having Puck teach Alex magic, which Oberon accepted. Grateful to the gargoyles for coming to Alex’s rescue, Xanatos promised to do whatever he could to repay them.
He showed this in two ways. First, he helped solve Coldstone’s multiple personality problem by building robotic bodies to house the souls of Desdemona and Iago, although he needed some help from Puck and Alexander in completing the process. Second, when the Clock Tower was destroyed by the Hunters and the gargoyles subsequently trapped by the Gargoyle Task Force at St. Damien’s Cathedral, Xanatos rescued the clan and offered them their old home in the castle, with "no catch, no plot, no strings." The feud was over. Since then, he has kept them safe from their enemies there.
Xanatos is a strongly practical man. He considers revenge foolish and beneath him; what motivates his various actions, instead, is his practical goals. One of these is to increase his current power and influence, and that of Xanatos Enterprises; it was for this purpose that he acquired or sought to acquire such followers as the gargoyles, the Pack, and the Mutates (not to mention such employees as Owen and Sevarius).
Xanatos has no interest in taking over the world, for the simple reason that he doesn’t see any need to; he’s been able to accomplish the greater part of his goals under the current system.
Another goal of Xanatos is to become immortal, since he secretly fears old age and death - just as he fears anything that he can’t control. He has made several such efforts at it, including the Cauldron of Life incident, and employing the Emir to capture Anubis; these efforts all failed, however. Xanatos, indeed, will eventually die, at some point before 2198; however, in a deeper sense, he will gain immortality through his son Alexander. Before this time, he will go into partnership with Lexington, changing Xanatos Enterprises into the Lexington-Xanatos Corporation.
Unlike many of the gargoyles’ enemies, Xanatos’s style as a "villain" is best described as, not so much "evil" as "amoral". He bears Goliath and his clan no malice or grudge, and indeed, regards them with a combination of interest and amusement. His pursuit of them was motivated by the fact that he wanted to make use of them for his plans rather than out of a pointless grudge, and he had no difficulty (from his point of view) making peace with them after they saved his son. His various scheming activities are based simply on accomplishing what he wants done, rather than out of hatred or vengeance.
However, Xanatos is not completely heartless. He does love Fox very much (a revelation which actually took him by surprise), and their son Alex as well. He also does have a strong regard, deep down, for his father Petros, in spite of their somewhat strained relations, and took care to invite Petros both to his wedding and to Alex’s birth. His familial devotion serves as the other side of the coin to the smiling, machiavellian schemer.
While Xanatos is mainly a planner and trickster, he’s not afraid to go into battle himself when the situation calls for it. He is well trained in the martial arts, and for those occasions when he needs more than that, has a crimson battle suit in the shape of a Steel Clan robot to don. In this armor, he was even able to battle Goliath to a standstill. In all, Xanatos is a very formidable opponent, and one not to be taken lightly.