Genius Grandson of the Loan Shark King is a Manga/Manhwa/Manhua in english language, Drama series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Kim Mu-hyuk, the grandson of the Loan Shark King Cheon Tae-san, whom even the wealthy elites of South Korea bowed to, strives to be recognized as a member of the Cheon Family. Despite his efforts, Mu-Hyuk is betrayed and killed by his uncles in a vicious struggle over his grandfather’s inheritance.

However, instead of dying, he wakes up in the 1990’s, with a second chance to rewrite his fate. Determined to prevent the death of his grandmother, who raised him, and reclaim the legacy of the Cheon family, Mu-hyuk sets out to preserve his severed friendships and take brutal revenge on his uncles and anyone else who stands in his way.

Will Kim Mu-hyuk, the grandson of the loan shark king be able to ascend to the throne of the ruthless Loan Shark Empire, feared by even gangsters?