So many parallels to journey of flower! But I think the directors deliberately made the lead Bai Quan much more human and less of a happy go lucky (but lovable) airhead on purpose.  She has claws in this one.  That said...

This contains spoilers.

Our Bai Quan or Su Yin is heartbroken when the beautiful Li Jing a.k.a second ghost Prince has an affair with her (cousin?) Xuan Nu. She actually walks in on them. He says thy wouldn't work out because of her inability to abandon all and go with him.  He leaves with Xuan Nu and returns home even though it's been clear from early on that he is confused about his feelings for Xuan.  Well his father is not happy to see him and believing he will be killed Xuan Nu sells out her people to spy.  She is deeply in love.

This selling out appears to cause Like Jing to realize he never loved her.  He leaves without consummating their marriage and shortly after the power hungry first Prince shows up and drags her off to an unpleasant fate.  We later learn she has been brutally beaten and returned to Kunlan as a warning.  Bai Quan warns her to stay away or she might cut her.  An extremely bitter and vengeful Xuan Yu is shown planning to use the trick of appearing like Bai Quan to steal a military strategy from the war God.

That said, I am very sympathetic to Xuan Yu.  She tricked Li Jing once but he chose to keep sleeping with her after he found out dismissing the first time as h being g confused by alochol because she looks similar to Bai Quan.  At one point Xuan Yu even tells him to pretend it didn't happen but she loves him and is able to seduce him without any more tricks.  All is fair in love and war.

Now she literally throws everything away including her honor and family to keep him alive.  He abandons her by telling her he loves Bai Quan and then she is tortured (this may be part of ghost Kings plot) and her lover has abandoned her.  Naturally she will hate Bai Quan and want some payback.  It's very tragic.  And I don't excuse her behavior at all but her hate has a source and isn't random or odd.  She played a big hand and lost.  

Random funny thing: Dijun who I love bc he is so I dunno detached and has white hair is chatting about tea cups on the eve of celestial world war.

hello new Eternal Love viewer!! 
the drama just gets better as you go on! :D 

I think a lot of people hated  Xuan Nu, and I hated her too, but I also think she had legitimate reasons for doing what she did. I mean, her mom wanted her to marry a black bear (probably ugly) even though she herself is a fox. Any girl would have wanted to escape an arranged marriage if they could, and I think that was part of her motivation for trying in any way possible to get together with Li Jing. 

But at the same time, even though the way Li Jing treats her kinda sucks, it's not possible to force someone to return their feelings especially if they don't love you. Later on a similar story line occurs with Su Jin. 

The same director directed both Journey of Flower and Eternal Love, but the dramas are based on separate books by different others. But same xianxia fantasy feel. 

I looooveeee Bai Qian too. Her personality when she's a mortal is super cute and lovable too haha :D 
I really disliked Xuan Nu. At one point I just skipped her parts looool. 
Xuan Nu was always jealous of BQ, always hated her out of envy way before the black bear thing and Li Jing. I never felt any sympathy for her because Li Jing was never her lover, it was all her wishful thinking. I really don't recall him confessing his love for her. He slept with her like he slept with so many girls anyways. She was clear about who he loved, yet acted like she was the one betrayed. She would always try to force her way in with the most despicable tricks then blame her wicked heart on love. What I disliked the most is how she was a selfish and greedy monster spending her life lying to herself and others, even her own child was not spared. She did not love Li Jing, she wanted to have him and it's different, I even think it was deep down just to win against Bai Qian. She did not care about LJ's feelings, his thoughts, his ways, it was just about doing everything she can in hopes of owning him. The more she realized he loved BQ, the more obsessed she became.That selfish possessiveness passed as love like Su Jin. Considering all the wrong she did, I didn't like how they killed her.
I know lots of drama writers say love is possessive but when you totally disregard the feelings of the one you "love" up to trying to kill his own family @_@ I don't think it's really love...more like obsession and heavy delusion. Su Jin is the same type of character, except she got less people killed lol.