I have performed the GM task for most of my rpg career. Yet, a few characters stand out through the ages.
My first Vampire the Masquerade character was a Giovanni. This would lead to me running a full-on campaign of Giovanni (and related sub-Clans) while I was living in Memphis.
My first character in one of Lowell’s games was a Werewolf the Apocalypse character named Merik. Despite a really bad player, the game was awesome. It also showed the inherit flaws of the rule system’s combat damage mechanics. What do you mean I’m a nine foot tall werewolf who just did no damage on a 6 die successful attack roll?
Then, there was Ur-Traczek Qingu Adapa-apkallu the Gunslinging Goblin in Steve’s Freeport True20 game. We called him “Ur” for short. He started with an eyepatch that he didn’t need. It covered his “shooting eye”. He ended with a sombrero no one needed. Where the werewolf character was flawed at dealing damage, Ur was a powerhouse to rival any other powerhouse in the party, except for the magic users. He had more guns than teeth and didn’t believe in waiting for the rest of the party to catch up before moving on to the next room (or five) in dungeons. Ur was different for me, because he wasn’t cautious, he wasn’t worried about being cut-off from the rest of the party, and I didn’t try to be in charge with him. Not that he was a beta personality, either. He was a solo adventurer in his own world and the rest of the party was there to back him up as needed.
He may have also been a bit of comedic relief.
That leaves my D&D 3rd edition, half-orc. This poor boy was an orphan, adopted by humans in a very human-centric village. He was a ranger, carrying on the tradition of his adopted father. He also stuttered, unless he was in combat. The players thought it was great that here I was, playing a stuttering, nervous, shy, giant sized half-orc. I had even managed to botch up some die rolls about ranger-y things before the first real combat, which helped sell the bumbling kid act. At soon as we went to initiative, the stuttering stopped, the shyness fell to the background, and the killing machine started. I did not get many feats with the half-orc ranger, but I maximized everything I could improve. He would eventually manage to use a magic scroll to kill off a troll as we reclaimed a keep for the baron (or whomever it was). That was likely the highlight of his life. Kip ran a great game and the group was a lot of fun when they got along. Sadly, personality issues crashed our group within 3 years.