Personality: Oddly enough, Schuldig is the most carefree of the four Schwarz members, or at least he appears to be. A grin or smirk is more likely to be found on his face than his teammates. Unfortunately the things that bring him pleasure are hurting both him self and other people, mainly other people, making him both sadistic and masochistic. He is a strong telepath, but has little ability to block out the "noise" he is hearing, which likely has lead to some of his insanity.
Schuldig is also irritating. He is arrogant, loud, and overwhelming the majority of the time he is talking to someone. He likes manipulating and annoying people. He is at his most talkative when there is someone around to taunt or manipulating someone. Other times, he tends to be more direct. He dislikes order and is often fighting with Crawford, the leader of the team. He also is of the opinion that he is better than other people. Schuldig will often mock members of his own team at times. He is manipulative, often making himself seem like a gentleman or that he is the one being misunderstood to get people listen to him and do what he wants. He claims that people's minds taste like honey.
Schuldig has a disregard for authority and really has no ability to care about others even those he works with at times. He also tends to enjoy playing with minds to the point where he forgets what he is actually supposed to be doing.
It can be said that Schuldig has an obsessive personality. He tends to be obsessed with wanting to harm people, to torment people. It is possible that this would carry over into vices, such as smoking or drinking. It is a possibility in my opinion that he would drink. Since he admits that he sometimes can't tell the difference between his thoughts and those of others, he might drink in order to quiet the external voice.
Strengths: Schuldig is a powerful telepath. He is able to read people minds very easily and able to manipulate them either with the thoughts he has gathered or by manipulating the thoughts themselves. In series, he communicates with Nagi and Farfarello by essentially listening to their thoughts directed at him and replying back with his own thoughts. He also has the ability to run unnaturally fast and jump great heights, leaping up from drastically lower buildings to reach an upper level balcony where Omi and Takatori's daughter were located and seeming to appear out of nowhere to block the attacks on Omi's older brother. He is also skilled with firearms as this is his weapon of choice. Schuldig is very much in control of his emotions for the most part. If he feels sadness, regret, or fear, he does not show it. Everything remains hidden inside of him.
Weaknesses: Ironically, one of Schuldig's weaknesses is that he doesn't think at times. The fact that Takatori's daughter could have been killed when he was taunting Omi didn't seem to have occurred to him. Another weakness is his telepathy. While he is a strong telepath, he once commented that there were times when he can't tell whether the thoughts in his head are his own or not. As such, he probably can't block or not very well and might be just as susceptible to someone reading his own thoughts. One emotional weakness is that he can't form deep attachments to anyone, including his own teammates, to the point where he teases and mocks even them... especially the youngest, Nagi. Another weakness is that he does have the tendency to panick when his plans do happened to fail, such as when the attempt to draw Weiss out with Takatori's daughter failed. However, this does not happen often.
Since Schuldig does have the ability to mess mentally with other characters, I'm making a permissions post so I can know how far he is allowed to go with certain characters. If you have any preferences about Schuldig's interaction with your characters, if you want him to know something about them or not, or if you (for whatever reason you may have) want him to be able to influence what your character is thinking, feel free to let me know.