I'm Shadsie at most places.
I'm Lady Shadowcat over on the fanfiction network and on the Trigun message board I go to - Trinut. This is a throwback to older days.
The Evolution of My Online Handle:
Upon first gettinng an interent ready computer at home and discovering the world of fanfiction writing, I decided I needed a name. I looked down at my little gray cat, Shadow, and boom: "Shadowcat."
(I found out later, much to my embarassment, that this was an X-Men comics charracter I'd never heard of. I was mistaken for a fan of that character. Sigh).
I was known as "Shadowcat" in Pokemon fandom circles. I eventually started going by Lady Shadowcat when I found a few other "Shadowcats" out there (particularly on the fanfiction network). Most of my friends called me "Shadsie" or "Shads," so I just picked Shadsie and stuck with it, leaving the "Lady Shadowcat" name up at places where I'm too lazy to change it.
Back when I was into the Left Behind books *shudders, trying not to remember those days* I was on the message board for them as "Shadsie Darkchristian" and I got quite a bit of stern talking to by suspicious "uber-holy" people who didn't quite like the "Dark" in my name, nor that I was open that my other favorite books at the time were high fantasy (Tolkien and such). Some people just cannot accept that there are those of us who acknoweldge that the Bible is R rated and that life is a brutal thing... "darkness" and all. I left those boards years ago.
At a Christian anime board (to which I also never want to return), I was Haibane Shadsie - owing to my love of the anime "Haibane Renmei" which was at a fever-pitch at the time...
Let's see.... I go by Shadsie Saverem over on AIM... it's a name I'm too lazy to change. The "Saverem" bit is from the anime, Trigun. It's the last name of a character who sacrifices herself to save many people. Some of the fandom hates her, I'm one of the ones who always loved her, so... I took her name.
I went by "Lushdesolation" for a while on Live Journal, having created the journal when I lived in Arizona. It comes from a line of a poem I once wrote about the Sonoran Desert being a place of "lush desolation."
I think I still have the "Lonesomepudding" name over on Journalfen - but I don't go there anymore and only created the account to defend myself and friends on Fandom Wank when people would put us up there for mockery. Let me tell you, once you're put on there, defending or explaining your actions, or even calliing for a little mercy does not work. Everyone's pretty much already judged you as worthless, end of story. I think the name came out of something Trigunnish, but I can't remember the exact origin, and it it doesn't mattter, as it's a long dead account. I only note it because I think that name is still on the JF system.
You asked for aliases, you got them.
Pretty much, though, in current use are Shadsie, Lady Shadowcat and Shadsie Saverem - that's it.