Korean Odyssey held a lot of potential. And the Male Lead's performance was great. I also thoroughly loved the frenemies dynamic between the Male Lead and the Devil King.
The romance came in and out of being great and being draggy and repetitive. Plus the Female Lead, the "chosen one" if you will, was little more than a damsel with a ton of character flaws that would've realistically killed her off even before the events of this story.
The fight scenes were anticlimactic, like a kids show - so that didn't help with keeping your attention either.
Overall, I still liked it. But the appeal is very much with the support characters and the dynamics between everyone. The romance and the world-saving plot line weren't the best, and the Female Lead (character wise) was a misfit for the story. So, maybe try a couple more episodes to see if the support characters grab you enough and if not, then drop.