Severus Snape

A person who had a clear logical thinking (few wizards can boast of this[9]). In the book "Harry Potter and the Philosopher's Stone" Hermione solves a logical problem with potions, created by Professor Snape.
A calculating strategist, a skilled tactician.
A person who is able to hide his feelings perfectly if it is necessary for the business.
Not a bad psychologist. At least finding the "pain point" of the interlocutor for Snape does not seem particularly difficult.

Snape can't be called a light wizard, but he wasn't a dark wizard. He invented spells, at least one of which could easily kill a person. He knew how to summon a corporeal Patronus.

An outstanding potion maker, he improved the compositions and methods of preparing potions.
A talented and very powerful occlumenist.
An outstanding wizard, who had an excellent command of magic. In this regard, he was no worse than Bellatrix Lestrange and Antonin Dolohov. Creator of new spells. In particular, Levicorpus and Sectumsempra.
A wizard who could move through the air without any means of transport (other than Snape, only Voldemort demonstrated this ability).
He was skilled in Legilimency. In particular, Severus taught Potter to protect his consciousness from the Dark Lord.

Snape was a thin man with pale skin, a hooked nose, and greasy, shoulder-length hair. His cold, black eyes resembled "dark tunnels": they were as black as Hagrid's, but lacked the warmth that shone in the giant's eyes. Snape was of average height, with thin lips that often curved into a mocking smile. He spoke in a soft, low voice, though with a hint of steel. He could silence a noisy class with a soft whisper.

His [Snape's] eyes were black, like Hagrid's, but they lacked the warmth that shone in the giant's. Snape's eyes were cold and empty, somehow reminiscent of dark tunnels.
Harry Potter and the Philosopher's Stone

Snape preferred to wear black, flowing robes, which gave him the appearance of a bat. In general, Snape paid little attention to his appearance. His perpetually greasy, unwashed hair was the subject of ridicule and jokes. According to Rowling, he placed more importance on his inner world than his appearance.

Severus Snape is a sullen and unsociable man, cold in his dealings with people. He is strict with his students (to the point of becoming Neville Longbottom's worst nightmare), making an exception only for the Slytherins. But at the same time, Snape is sincere and noble: it was he who protected Harry his entire life, it was Snape who told Dumbledore of Voldemort's plans to kill the entire Potter family, it was he who secretly gave Harry the sword of Gryffindor. Even killing Dumbledore was not a crime: it turns out that the headmaster, tormented by Marvolo Gaunt's cursed ring, literally begged Severus to kill him.