Blood Sip, Skill Snack

In another world, I snagged a wicked skill. A skill that lets me copy someone's powers and looks by drinking their blood. Sounds like an ultimate cheat, right? But there's a catch: it's worthless unless I can actually draw blood from them. And somehow, after a helluva struggle, I even managed to slurp up the Demon Lord's blood! Thought I was set for an epic cheat life in another world! But then, bam, back to Korea. Except...why are there monsters here too? — Description from novelcodex.org