What were some of your (general audience of this post) favorite characters ever?
A PC in my first long-running Rolemaster campaign was a sorcerer, which is the RM version of a dark-but-not-necromantic wizard. He would cast acid bolts and acid balls, scour opponents' souls, sometime take command of them by "banishing" fragments of their souls into soul objects (a bit like a reverse "magic jar"), and he could also disintegrate pretty large structures.
Xialath had been born into slavery, but at a certain point (in his backstory) had bought his freedom, and was a lawyer in his home city. Mechanically, he had noticeably high social and perception skills for a mage, which he had traded off against meditation skills. This proved to be (part of) his undoing.
He leased a house in his city, with a servant to deal with the riff raff, and in the basement a pit of acid that he would use to dispose of enemies of the need arose.
The other PCs were also mostly wizards. They all had meditation, which allowed them to regain their power points more quickly. On one occasion, Xialath needed to recover his power points quickly to keep up with his comrades, and so he purchases a mind-affecting root - Hugar (statted out in the RM herbs and drugs list) - from a shadowy character at the local market. It did the job, but the player failed the addiction roll, and so he spent more and more of his money on Hugar. When his annual lease payment on his home fell due he couldn't pay, and was evicted.
Around this time, one of the other PCs was reaching an agreement with Vecna (in this campaign a lich who had been in torpor for a long time, but had been returned to "life" by the PCs) to join with him, and with the forces of a neighbouring empire, to conquer the city he and Xialath hailed from. This PC persuaded Xialath to join in this effort, in exchange for a promise of restoration of his house, and the granting of a magistracy. So Xialath betrayed his home city out of greed. The other PC arranged for healing (Cure Mind Disease True, and probably also some Organ Healing) to end the Hugar addiction.
At the same time as his personal life was collapsing in these ways Xialath also suffered misadventure "in the field". That other PCs was a demon summoner, and on one occasion the two characters were flying through a great mountain range in a demonic skiff (under the control of the summoner PC). Sky giants spotted them, and hurled boulders at them; one of these struck Xialath and he fell to earth, suffering terrible injuries and having to be restored to life by a different faction of wizards.
In RM there is always a risk of losing control of a summoned demon, and on a subsequent occasion the two PCs were standing on a conjured floating platform above the abandoned castle they were investigating (at Vecna's behest, as best I recall) with a summoned demon that went rogue, and pushed Xialath from the platform. I think it was agreed that this would cause Xialath to suffer a Depression crit, and the roll for this was terrible. He collapsed, catatonic, in the wilderness outside the castle.
Xialath was recovered by a (NPC) Valley Elf scout, who had been spying on the PCs at the behest of the Mage of the Valley. She brought him back to consciousness, and abandoned her loyalty to the Mage in order to return with him to his home town. She was a shapechanging mage (a Mystic, in RM terms) and the two of them would shapechange into griffons and frolic in the skies above the city.
She accompanied the PCs on a mission to the minotaur-ruled caverns beneath another mountain range. Another summoned demon escaped control, and cut her in half (RM crits vs RM mage defences and hit points can be quite severe). As a result, Xialath once again spiralled into depression, addiction (alcohol at least, and maybe Hugar again - I don't remember now). He had to be magically restored to health again to head off on the final mission of that campaign, his goal being to recover sufficient money to pay for the mighty magic that would be needed to restore his beloved to life. Unfortunately, that mission was fatal for all the PCs, who died to a fireball in another dimension.
That player came up with other memorable PCs, but Xialath is the one I remember best.