David Xanatos was a ruthless individual and master of manipulation who rarely got himself involved personally with a battle, preferring to utilise his wealth and power as weapons of their own - he also created the Steel Clan, robotic versions of the Gargoyles and he personally donned a Steel Clan robot suit on several occassions in order to make himself a physical match for Goliath and his clan.
However Xanatos' most dangerous weapon was always his mind, a genius in many ways and holding enough influence that he could get away with his illegal dealings (though even Xanatos is not fully immune to the law as he has spent a few months in prison due to being in possession of stolen property - his sentence greatly reduced due to his network of lawyers). Throughout his carrer Xanatos was aided by his henchman Owen Burnet (who is in reality the Fay known as Puck): who was willing to do anything for his superior.
Xanatos' efforts to create replacements for the gargoyles resulted in the creation of the Mutates and Thailog - however Xanatos made a mistake in creating Thailog as the clone learnt a little too much from Xanatos, proceeding to rob him for 20 million dollars before breaking off to become a new rival.
Shortly before his marriage with Fox David Xanatos became a member of the legendary Illuminati - though is ranked as one of the lowest.
David Xanatos' war with the gargoyles would only truly come to an end after the birth of his son, Alexander, the clan helped rescue Alexander from Oberon (though they had little success - rather the day was saved by negotiation on Goliath's behalf). Thankful to his former enemies for saving his son Xanatos finally put aside his long-running rivalry with the clan and dedicated himself to helping them.
David Xanatos is an extremely practical man who thinks of revenge as a pointless concept and concerns himself purely with increasing his current power and wealth as well as his business - he has no interest in taking over the world as he finds himself able to manipulate the current laws of society sufficiently to accomplish his tasks and in the end he could be considered a brilliant businessman: however in order to have such brilliance Xanatos is willing to sacrifice such things as ethics and morality.
Despite his ruthless personality Xanatos is a geniunely caring father and husband and when with his family David Xanatos is a much more sympathetic individual - at least for a little while.