To make a long story short, saw the name Xenon in a science manual in high school, under an illustration showing the various inert gases and how they lit up when an electrical current passed through them.
I liked the way it sounded and loved the color of it, but it wasn't until I found a name dictionary and saw what it meant that I went head-over-heels for it.
So the classic meaning to the name Xenon would be "the stranger, the alien, the odd one, the one who doesn't belong, the different" I felt that stretching it a bit could mean "the unique one". As I never managed to fit in as a teenager, it felt simply perfect.
As for the Wulf part, I thought that using that Xenon bit and turning it into a way of saying "the lone wolf" into something which could be passed off as a real name was a nice touch, so I tried to change Wolf into something which could conceivably be used as a last name.
It also served a second purpose as a reminder of what I had been through, as the family name of one of the worse bullies I've had to deal with in high school was Wolf (or some variant thereof).
I've been using the nick for so long now that it's second nature - I'll use it for 90% of what I do online.