Payback (2022)

Blurb:
Lee Yoohan had lived life as a thug, playing by his own rules and caring only for his own indulgences, with no regard for others. As a consequence of his past actions, his younger brother was tragically murdered, followed by the death of his mother. Then alone in the world, his sole purpose in life was paying off the debt incurred from his mother’s hospital bills. The same day he scattered his mother’s ashes, he ended up spending the night with a stranger …

Five years later, after repaying his debts, Yoohan overheard his ex, Song Myungshin, and learned the truth behind the pivotal day. Determined to seek revenge, he embarked on an acting career. In this new world, he met a lunatic who demanded a fortune for a half-burned cigarette and bizarrely offered to sponsor him. But what secrets was this lunatic hiding?

Source: www.anisearch.com/manga/89164