PS: This is the worst comment I type in my life and I hate the person who suggested me this drama (whoever that is)
I don't understand why people love this. There are thousands of reasons not to like this.

I know that different people have different tastes. But do you call this a good chemistry? Am I the only one felt cringey watching the main couple and wanted to skip?  I mean the FL was not that comfortable with the ML!
Even though they are good actors, and acted some parts amazingly, sometimes the acting is a bit dramatic, forced and didn't feel real.
Some of the first few episodes were good and had some kind of an interesting story that I could enjoy.

But after the first story ended, everything was totally about the main couple's love story. And it's not even that interesting. Maybe it could be interesting if it was shorter. There were like 5 minutes of interesting parts for once in 5 episodes.
The whole story is focusing on the ML and the FL and the writer did not care about what happens to the other characters and all the other characters were just background characters for their love story. They just come and do their part for the main couple's love.
I absolutely hate the way they ended the story of Xiao qi. He was the only character I liked. (Yun hen was also a bit interesting)

I was expecting a legend, but there was just a boring love story. The writer tried to make their background story an amazing back story, but for me, it was ruined with long and boring scenes. Right when I think oh it's getting interesting, he cuts off that interesting feeling with something annoying.

The drama is also full of childish jealousy and bullying which I hate to see in a drama. Normally I avoid these cruel continuous bullying dramas. I think adding more scenes like this promotes bullying, and it should be stopped!

I've never fast forwarded a drama, (I watch average 2 dramas a month, at least 5 historical cdramas a year) but I fast forwarded almost all the last 10 episodes of this drama while cursing the person who suggested me this. I felt so relieved after finishing the last episode. I was like "thank god it ended".
I've watched dramas that focus a lot on the main couple, and I could enjoy them even though I'm not a big fan of romantic dramas. But this is annoying and boring than interesting.
Finally, this is my least favourite drama I've watched for the past 4 years. I've wasted 2 months of my life!
Again, I know different people have different opinions and tastes and this is just my opinion.