"The snowflakes on the seventh night bloom and and wither like a short reunion and a permanent separation."
This encapsulates the whole story.

"Eternal separation"
This applies to the main couple and the siblings in the story. The saddest and most brief reunion is Miao Feng (Prince Ya Mi) and his sister (Princess Shan Mi). There were many hints of their ending throughout the drama but when I saw the former valley chief and the 5th sword sect disciple I thought it would be the future of Zhan Bai and Zi Ye. I think Qing Ran and 5th were the only happy couple in the story.

Love is expressed in many ways.
Siblings love either blood and non blood related, strangers to long lasting friends to lovers, secret love, love expressed more through actions than words, parent to child, friends, sworn siblings, master-disciple, enemies...
Huo Zhan Bai and Xue Zi Ye's love is expressed more through their actions. Their love language is sometimes funny and sometimes sweet and funny.

Obsession has its consequences.
It happened to all of them including the villain which led to his demise. He never expected the kids he raised as killing machines would one day turn against him. That's the best ending for a lunatic and manipulative like him, he deserves it.
Xue Zi Ye was obsessed with bringing someone to life, Huo Zhan Bai's finding cure for Mo, Miao Feng's protecting the villain who he thought saved him but what happened was opposite. Miao Shui was on avenging her while family which she didn't expect M.F to be her only family left. Eye's is his freedom. The villain Chang Wu Jue is dominating the martial world. Seven's sworn bro, 6th disciple's is becoming the next Sword Sect chief. Mo's mother's is getting attention. She married on impulse the 6th disciple but was still in love with Seven and wanted his attention (accdg to novel readers). It's unfortunate how their obsessions controlled them for years and missed important opportunities until it was too late.

Still too late
Huo Zhan Bai couldn't save Mo but it wasn't his fault. It was his junior, Mo's mother, Qui Shui Yin. The fake prescription given by Zi Ye saved both her and Zhan Bai for 8 yrs so she can't be blamed because it was a critical time. He also couldn't save Zi Ye. His letter missed her, he was a day late to see Zi Ye alive. They could have met but he was too focused on his mission. Too late to realize he already met the dying Zi Ye.

I like how Zi Ye was a big part to the downfall of the he villain and how the siblings joined hands to kill him. He owed them. Blood for blood.
Zi Ye did so much before she died so I think she felt fulfilled. Miao Feng and Huo Zhanbai's (Seven) reactions to the death of Zi Ye are very well performed, emotionally wrecking. Zhan Bai's blurry vision and him in his old age cleaning Zi Ye's tomb are depressing.

I now understand why Zhan Bai and his gang were late because what they had to deal with is one of their people who was still in deep obsession ,6th disciple Xu Chong Hua.

I loved the start of their story ,the repetitive routine of Zhan Bai and Zi Ye for 8 yrs. There were subtle changes to their relationship. When Zi Ye thought Zhan Bai almost died from his very serious and heavy injuries, it was the first time she cried and she realized how important he was to her.After that, she learned to let go of her obsession.

Wang Hong Yi as Miao Feng is visually the most outstanding to me with his blue hair and his simple white and cream costume against the snow, very handsome smile too. He looks different when he plays his instrument looking like a snow prince. His fight scenes are amazing too, He's actually also very powerful in the martial world but he preferred to be the next valley chief, protecting the valley and become a healer like Zi Ye. I like his and Zi Ye's moments together because they also have an irresistible chemistry although only he had a crush on her. She helped revive the Ya Mi in him and helped him reunite with her sister and let go of his obsession . His performance was on point although his longest screen times were during the last few episodes.
Joseph Zheng's most attractive costume is the white one with dark blue prints. His high ponytails, side curls, and his fight scenes make him more attractive as Huo Zhan Bai. He is funniest is when he forced his snow harrier to listen to his troubled mind. His sweetest moment with Li Qin as Zi Ye was with witnessing the epiphyllium blooming, the night they spend together under the plum blossom tree, and when he was slowly realizing his feelings for her, his eyes were fixed on her, those long gazes when Zi Ye was healing her and she was too close to him.
Li Qin is so beautiful in her simple costume, make up and with less jewelries on her hair. Her purple dress matched the beauty of the snow and snowy landscape, her hair flowing with the wind. The way she holds the needles and performs healing look sexy and beautiful.
Everyone performed well.
Edward Chen's acting as Eye or Mingjie is also memorable. His role is not my favorite but his acting is convincing. He performed well. I hope he gets more roles in the future.

I never loved sad tragic endings but this drama executed it beautifully and smoothly that's it's very memorable including the 6 osts I will miss listening to them while watching the drama. Joseph Zheng's ost is my favorite but all 6 were melancholically beautiful to my ears.

Don't forget to watch it til the end for that bonus clip! It's the happy ending we wanted, better than the novel ending. For that reason, I'm giving this an extra 0.5 that it deserves.