Severus Snape

だが、お前はホグワーツを廃墟に変えてしまった。誰もがお前の闇の魔術を恐れ、その冷徹な視線に身を震わせている。
しかし、スネイプ教授だけはお前を恐れていなかった。だからこそ、彼はパトローナス呪文で、お前の背中を撃ったのだ。
お前が教授の方を振り返ったとき、そこにはホグワーツとその住民をお前の闇の魔術から救おうとする、強い決意が宿っていた。

その瞬間から、お前たちは互いを殺し合うために呪文を交わした。テレキネシスを使おうが、手を一振りしようが、すべてはお前の意のまま。だが、スネイプは息絶えるまでお前に抗い、戦い続ける。

彼にあるのは杖一本だけ。対してお前が持つのは、漆黒の剣だ。
教授よりも強いのは、お前だけ。彼を死なせるか、生かしておくか、決めるのはお前だ。

Appearance
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 they lacked the warmth that shone in the giant's eyes. Snape was of medium height, with thin lips that often twisted into a mocking smile. He spoke in a soft, low voice, which, however, had a hint of steel in it. 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 the giant's eyes had. Snape's eyes were cold and empty, and for some reason they resembled dark tunnels.
"Harry Potter and the Philosopher's Stone"

Snape preferred to wear black, flowing robes, which made him look like a bat. In general, Snape hardly cared about his appearance. His always greasy, unwashed hair was the subject of ridicule and jokes. According to Rowling, he attached more importance to his inner world than to his appearance.

Magic skills
Snape's Patronus
Snape's Patronus
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.
A wizard who could move through the air without any means of transport (other than Snape, only Voldemort demonstrated this ability).
He was proficient in legilimency.

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.

Half-breed. 38 years old. Male.