Pick Up a Grimoire, Become a Mage

A brief description of the manhwa Pick Up a Grimoire, Become a Mage:

An ordinary college student has his life upended after stumbling upon an ancient grimoire in a secondhand bookstore. Bound by a dangerous contract to an invisible vampire with a lethal, bloodthirsty instinct, he is thrust into a world of dark shadows and hidden threats. Keeping his supernatural alter ego concealed from everyday society, he embarks on a perilous journey to master arcane secrets and grow into a formidable sorcerer in this thrilling modern occult fantasy.