Severus Snape: Always

Explanation: Severus Tobias Snape. His first name comes from the Latin word for "severe"; his middle name Tobias comes from his alcoholic Muggle father. The surname Snape is English, contrasting with Prince (his mother''s wizarding surname).

Explanation: Eileen Prince. It''s from her maiden name (Prince) that Severus takes his nickname "The Half-Blood Prince" — half-blood because his mother was a witch but his father Tobias a Muggle. Eileen was captain of the Gobstones Club at Hogwarts.

Explanation: Spinner''s End. It''s also where Lily Evans lived as a child (his neighbour), which is how their childhood friendship began. In Book 6, Snape takes the famous Unbreakable Vow to Narcissa Malfoy there, with Bellatrix as bonder.

Explanation: A doe — the same form as Lily Evans''s. His Patronus guides Harry to the Sword of Gryffindor in the forest in Book 7. When Dumbledore sees Snape''s Patronus years after Lily''s death, he exclaims "After all this time?" — Snape replies "Always".

Explanation: "Always". Spoken in Dumbledore''s memory when the Headmaster asks, amazed, whether Snape still loves Lily after all these years, Snape conjures his doe Patronus and simply replies "Always". The saga''s most iconic line.

Explanation: A double agent (some readers call him triple). A Death Eater serving Voldemort, yet loyal to Dumbledore who promised to protect Lily''s son. He takes enormous risks feeding the Order intelligence from the inside. Harry only understands at the very end.

Explanation: Head of Slytherin House. Equivalent role to McGonagall for Gryffindor, Flitwick for Ravenclaw, Sprout for Hufflepuff. He openly favours his students and awards Slytherin many points, much to Harry''s irritation.

Explanation: Through his tears. Dying from Nagini''s bite, Snape extracts a silvery flood of memories from his temple and begs Harry to take them. Harry collects them in a flask and views them in the Pensieve — revealing 17 years of true loyalty to Dumbledore.

Explanation: Defence Against the Dark Arts professor. Dumbledore always refuses — the post is cursed (no one keeps it more than a year) and Dumbledore fears it would awaken Snape''s dark side. He finally accepts in Book 6, so Slughorn can take Potions.

Explanation: Headmaster of Hogwarts (1997-1998). Imposed by Voldemort after Dumbledore''s death, he quietly tries to protect students from the Carrows — two Death Eaters teaching Dark magic and torturing rebellious students. McGonagall drives him out at the start of the Battle.