The Umbrella Academy's Leonard Peabody is a vastly different character in the original comic books. In Netflix's live-action adaptation of The Umbrella Academy, Peabody first appears as a mild-mannered, unassuming violin student who takes a liking to Vanya, but his stalker-like actions are soon called into question by both viewers and the other Hargreeves siblings. Having been the black sheep of the Academy, Vanya believes these suspicions to be borne of jealously, and she sides with Leonard as their relationship becomes more serious.
Eventually, of course, Leonard is revealed to be the fabled Harold Jenkins - the person who will supposedly bring about the end of the world. Born on the same day as the other super-powered kids, Harold tried to escape his miserable existence by joining the Umbrella Academy but was turned away, since he wasn't one of the 43 babies who had been miraculously birthed. Like Vanya, he wasn't deemed special enough. Using knowledge gained from Reginald Hargreeves' journal, Leonard manipulates Vanya into unleashing her inner power and attempts to make her use it against the other siblings in revenge.
In the original comic books by Gerard Way and Gabriel Ba, the Leonard Peabody character is very different. The villain is simply known as "the Conductor" but his function in the story runs parallel to Peabody's in the Netflix TV series. The Conductor spots Vanya's latent abilities and attempts to coax them out of her. Although she initially refuses to participate in the his schemes, the breakdown of Vanya's family ties forces her to reconsider the Conductor's offer, and he duly unlocks her abilities, finally transforming Vanya into the White Violin.
Visually, the Conductor is very different from Leonard. With a skeletal form, vampiric dress sense and an ominous name, the Conductor is far more of a bona fide supervillain that the everyday, unremarkable Leonard Peabody, and his gothic style is perhaps informed by Gerard Way's background as the vocalist of My Chemical Romance.
While the Conductor and Leonard may have similar aims, their methods are somewhat different. Instead of romancing Vanya and manipulating her, the Conductor openly offers to unlock her powers if she agrees to participate in a performance of his newly-composed masterpiece - a piece of music known as "The Apocalypse Suite" that will be played by criminals and madmen and bring about the end of the world. The Conductor pursues Vanya just as feverishly as Leonard does on TV, but rather than manipulate her emotionally, he straight-up brainwashes the violinist into realizing her true power.
The Conductor and Leonard Peabody may differ considerably between The Umbrella Academy's comic and TV variants, but both versions work wonderfully within their respective mediums. In the more offbeat comic series, it suits both the style and story to have a more overblown, obvious villain whose outside appearance is as dark as their soul. On the more grounded Netflix series, however, the innocent-looking Leonard is a more realistic interpretation of the sane character, and his betrayal of Vanya's feelings makes for a more engaging long term arc than a mysterious composer repeatedly asking her to play a song.
Perhaps this fine balance is the key to The Umbrella Academy's success - knowing how to alter a character to make them more suited to the format, but still incorporating enough elements from the comics so that the comic book inspirations are clear.
The Umbrella Academy season 2 is currently without a release date. More news as it arrives.