I, Who Used To Be An Idiot, Was Possessed By An Idol?! summary:

"Hyunsoo, who lived a decent life doing all kinds of odd jobs alone without parents, relatives, or siblings. He even did things like dumping things! Then one day, when he opened his eyes after a near-death experience... he had possessed an idol?! An idol? A member? The internet? At least 50 years had passed since Hyunsoo lived, so there was everything he didn't know. And on top of that, they were on the verge of disbanding...! In an instant, Hyunsoo, who had lost his way to live, appears in front of him the savior of the group 'Technician', Cha Soo-hyun. But this person... looks exactly like the master Hyunsoo used to serve...?!"