The Underdark itself is not the actual problem. I've been on this server for two or three months. In all my characters I have rarely left the confines of Sanctuary to venture out into the Underdark. I've had little reason to do it and my characters looked at it as a very dangerous place. I could not take you from the Gates of the city to Fort Mur by walking without getting seriously lost.
The problem is the feeling of security within the city itself. People don't seem to realize just how bad off the city really is - it seems that most people (and yes I am guilty of it as well) act as if they are staying in the Hilton. One of the main sources of meat most citizens eat is from rats and beetles. Rothe is more of a luxury.
People sit behind the walls of Sanctuary and are not actively involved in the city itself. This reflects in all aspects - from Council Elections to Upper/Lower relations.
Most people within the city are Escaped Slaves, yet there does not seem to be a real fear of returning to slavery. The Seekers are supposed to be disliked because of the attention they attract toward the city, yet you really don't see any of that within the role-play.
Here is how I took things with Melrick.
Melrick was born on the surface to a poor farmer who didn't even own the land he lived on. He lived in a small village and was moderately educated by a local Priest of Oghma who taught many of the village children. He worked the fields with his father, and he loved his family - he had a younger brother and sister. His mother died giving birth to his sister. He hated being a farmer, he saw it as a dead end, and he wanted desperately to provide more for his family like any good son. He joined the village Militia where he learned the basics of combat. Two years after this there was a bad year for his Father and the wealthy merchant who owned his farm decided to reclaim it when his Father couldn't afford the payments. Melrick's father committed suicide shortly after that, and Melrick blamed the merchant for his Father's death - he killed the Merchant in a fit of anger and grief.
Fearing what would happen to him he fled the Village trying to make it to the nearest town. He decided that when he found a new place to live he would send for his brother and sister, but on his way he was captured by the Drow and taken into the Underdark.
He was tortured and he was enslaved. He held hope of escaping in the beginning and made several attempts but the Drow's cruelty eventually cut that notion from his mind. There was little he could do, but as is common in Humans in times of crisis he turned to the Gods.
Melrick began to eventually believe that someday he would be free, that his life was meant for more than simply serving the Drow. That he was more important than that. The seeds of evil were being planted then as he watched his Masters and learned from them. He looked for weaknesses, he watched their games with one another, and he always worked under the guise of absolute obedience - on the outside Melrick was the ideal slave. Strong, healthy, obedient, quick to learn and eager to please. On the inside Melrick was resentful, bitter, angry and he drew deeply on those emotions to give him strength to survive the ordeal. He worked hard to prove his worth to his Masters, because he knew that only through doing that could he keep the other Drow at bay. Drow that would want to hunt him for sport. Drow that would want to sacrifice him to Lolth.
He was used as a gladiator and was forced to fight against other slaves. Some he had forged friendships with and he was forced to kill them - or be killed by them. The Drow painstakingly seemed to pick those he was closest with to battle against. Melrick withdrew within himself to avoid making personal relationships with people he knew he would eventually have to kill.
He was used as a breeder for new slaves. Most Female Drow castrate their males to make them more docile and obedient, Melrick escaped this fate by becoming a breeder. This behavior degraded him in such a way that he grew to resent all physical pleasure, he hated what he was forced to do and the Drow took great pleasure in his psychological torture.
Yet, Melrick always had his faith which he drew strength from - a dark deity. He believed that this was a trial - that he was like raw ore being forged into a sword. He was currently within the forge, being shaped to become strong - to be stronger.
He spent his last several months as a slave to a Drow Noble House where he watched their political games with one another. He learned the art of Drow Treachery of subjugation before your betters until you were strong enough to overcome them.
When he escaped from slavery and found himself in Sanctuary he brought this past with him. He threw himself at Dungal Toboerski's feet and took the knowledge he had learned and used it to his advantage.
As I played Melrick in Sanctuary he was often distant from other people, or got falsely close to them through pretending to be something he was not - because he wanted something or needed to use them in a certain way. Though he did eventually get close to Kyle Briar - a Tiefling Priest of Kelemovor and Valarm (who he knew before he became a Spellguard Agent). Valarm and Melrick grew apart as House Toboerski drew more and more of Melrick's time and the Spellguard drew more and more of Valarms, but his relationship with Kyle was always strong and perhaps the only real relationship he had with another individual since the surface. Though Kyle himself struggled with his own inner demons (literally) Melrick also struggled with his and perhaps that is why they grew close on some level - they could relate to each other.
However, the circumstances of their relationship was eventually tested when Melrick had to offer Kyle two options. One of them required his abandonment of Kelemvor and the other called for Kyle's death. Kyle refused to abandon Kelemvor and Melrick was forced to kill him, and it was at that moment when Melrick lost the last bit of his Humanity. It was at that moment when Melrick became -truly- evil.
Killing Kyle effected Melrick in ways that were not readily visible but became gradually obvious. It was as if someone had opened Pandora's box and suddenly everything that seemed to be holding Melrick back was gone. His ambitions ran wild, his emotional connection to others was gone, he felt no remorse for any action he committed.
But always, always ALWAYS from the very beginning Melrick was motivated by one feeling either directly or indirectly and that was fear. He feared his own insecurities which lead to paranoia. He feared the power of others which lead him to murder and betrayal. He feared losing control of a situation so he became a manipulator. He feared being weak so he acted as if he was strong, and his strength came at the price of anyone who he saw stronger than himself. He would lay himself at the feet of those who he believed were stronger, and become useful only until he could betray them and destroy them - becoming stronger than they could have ever hoped to be.
Eventually all of this destroyed House Toboerski. It consumed many people directly or indirectly. His paranoia of betrayal and rivals lead him to lock himself away in the Toboerski Estate and work through surrogates. The more powerful Melrick became, the more his influence grew, the more his inner demons seemed to ripple outward - consuming and destroying all that was in their path.
If Melrick had been successful in his ambitions nothing would have satisfied him. He would have kept going on and on until he was killed. His ambitions knew no limits, but he didn't seek to become powerful for the sake of it. Everything he chased after was an illusion, giving a feeling of false security, and when he realized that he always had to grapple for more.
His evil stemmed directly from his time as a Drow slave. The torments he endured, the hardships he faced, and the fear of once again returning to a time when he was powerless. A time when all hope seemed lost was the driving force behind all that he did - even his most depraved actions.
For example, at one point Melrick had another character trapped within the Toboerski Estate. This character he treated like an animal. He stripped her of her name, he stripped her of dignity and self-worth. She had to walk around on all fours like a dog. She had to speak in third person using the name that he gave her. She had to obey his every word and command. She had to sit at his side like a loyal and faithful pet, so he could stroke her hair.
He used his control over her to intimidate others. To show them that "This is the POWER that I possess. This will be YOUR fate if you go against me." Yet, in reality he was projecting onto her what he feared the most - the way he saw himself deep down. He controlled her in such a way because it gave him the feeling of superiority. It gave him the feeling of being dominate and in control. And through the use of her in that way he liked how it could intimidate and aid him in the controlling of others.
Most people never saw those aspects of Melrick. Melrick was evil for a very good reason, and those reasons came directly from his time spent in slavery. How many other characters on the server have been greatly affected by slavery?
How big of an impact has slavery had on a character? How many people honestly believe that after spending even a single week as a Drow Slave would make you believe that "some Drow can be good"?
There should be a scripted Prelude that allows characters to witness this before arriving within the city. They should be shown the horrible evils that the Drow, Duergar and such commit - it might aid significantly in the atmosphere of the server.