I am so glad you ask. I am feeling like educating a young measly boy in the orchard like you..

Questism (which takes place within the Lookism and Viral Hit universe! We get Lookism cameos and Viral Hit references in the series a lot!) is a manhwa about a boy named Suhyeon Kim. He was once bullied, mocked, belittled, and more, alongside his good friend Gukja Yang. One day, Suhyeon starts to receive these strange quest windows.. They help him beat his bullies, become popular, etc. Wowie! He also takes every single person he's ever beaten under his wing into his crew, which I think is hilarious. Like everyone sitting here hating his guts and he's just like "you should join West Gangbuk.." LIKE LMAO?
Anyways, his ultimate goal in the quests is to defeat Yun Jo, another quest user. From what I understand, Yun Jo receives quests from a different source! All quests come from actual people, and Suhyeon + Yun Jo receive quests from different people. Yun Jo's has corrupted him and made him the "antagonist", while Suhyeon's goal is to stop Yun Jo from committing more heinous crimes! Yun Jo hasn;t explicitly done anything with evidence, but he did put Sechan (the previous North Gangbuk leader) into a coma by draining him of his mana and overall life source. He also does this to his own companions. Also, he brainwashed all of North Gangbuk just to take over everything..? So he's pretty terrible.
While the main plot is cool, I love the characters within the story. I've grown genuinely attached to characters like Daniel, who sucked up to Yun Jo in order to protect Haru and complete Sechan's dying wish (although he isn't technically dead) to protect him; Jaeha, who is just completely rabid and is genuinely horrifying (his fight with the redhead made me SCREAM because why was he so DEVIOUS?); Hajun, who is being trained by THE Zack Lee from Lookism and has completely changed my view on him as an ex-protagonist (honestly, my view of him was never all that bad. He just needed to be humbled.); Seok, who has a strong sense of unity and genuinely only joined West Gangbuk to eventually reunite South Gangbuk (poor guy doesn't know how to accept the fact that he's cooked); and SO many more. The characters are genuinely so good and easy to love and adore! I also love that we get some LGBTQ content in Questism (I.e. Haru's unconfirmed gender identity (although please note that he uses he/him!) and Daniel + Sechan having feelings for Haru)) because you don't really see that in a lot of action manhwas!

Anyways that should sum it up. Thank you for coming to my TED Talk.