Lord Voldemort

Tom Marvolo Riddle (December 31, 1926 - May 2, 1998), better known as Lord Voldemort, is the main antagonist of the Harry Potter franchise.

He serves as the overarching antagonist of the Philosopher's Stone, Goblet of Fire, Order of the Phoenix and Half-Blood Prince, his Diary Horcrux serving as one of the two main antagonists (alongside Lucius Malfoy) of Chamber of Secrets, the unseen overarching antagonist of Prisoner of Azkaban, the main antagonist of Deathly Hallows and the posthumous overarching antagonist of the Cursed Child.

He is the heir of Salazar Slytherin who was destined to open the Chamber of Secrets and purge Hogwarts from all Muggle-born students. Initially, Riddle's goals were only to fulfill his role as Slytherin's heir, but over time, he had expanded his ambitions into taking over the entire wizard world and shape it under his and Slytherin's supremacist views, becoming the most powerful and feared Dark Wizard of all time above Gellert Grindelwald, as well as the founder and Lord of the Death Eaters in the process. He also serves as Harry Potter's archenemy.

Description
In his early years, Tom Riddle was an extremely handsome boy. He was described as having jet black hair, perfectly carved features, and dark eyes. The novel further elaborated him being virtually identical to his father and devoid of traces of Gaunts in him. As he grew up, his involvement in the Dark Arts gradually deformed his appearance; in the flashback of him requesting a position at Hogwarts, he had become deathly pale, his face waxy and oddly distorted, and the white of his eyes now had a permanently bloody look. Afterwards, he continued to go through many transformations, until he became what he is.

He is tall, and skeletally thin. His face is an almost opaque texture, with deep, dark scarlet red eyes set in slits, like a cat's gleaming in the dark. His nose is as flat as a snake's, leaving small incisions for nostrils, and his fingers are unnaturally long, like a spider's legs. He can usually be seen wearing his black hooded cloak that always covers his face.

In the films, his physical description remained same albeit with some changes; he was given blue eyes so they would "show more emotion" and when manifesting his face on the back of Quirrel's head while inhabiting him, his nose looked like normal instead of slits. Additionally, his restored body is shown to have very apparent veins on the top and back of his bald head (which some viewers misinterpreted as scale-like) and his eyes appeared normal instead of slits (Goblet of Fire film briefly showed him with slit-like eyes upon opening them however).