How to pass the eighth floor of Fairy Sword III Demon Locking Tower?

How to get to the seventh and eighth floors:

Go to the northwest of the eighth floor, there are stairs to climb up the corridor, and go around the Tai Chi array in the center to reach the seventh floor. I saw stone doors in two corners, but I couldn't get in at this time.

When you reach the seventh floor, you first stand at a crossroads. Take the road due north, and there will be a mechanism you can open as you go down. Go back to the original crossroads and go due west. At the end, you will meet an ice crystal girl (plot). She will give you a key and let you help her find her missing husband. After getting the key, go back to the eighth floor; go to the southeast corner of the eighth floor, open the door, and see the magic circle leading to the sixth floor. There is a small box next to it, which contains another key. At this time, you can go to the northwest corner. Open the door and get the big treasure chest. Then go back to the southeast corner and step on the magic circle to reach the sixth floor.

Water attribute treasure chest: behind the northwest stone door on the eighth floor of the Demon Locking Tower. Cuprite, dragon bone pendant, snow lotus essence, thyme, flowing wind powder, bone-penetrating amber: on the ground next to the water treasure chest.

◆Branch 15: Help Ice Crystal Girl find her missing lover. In the future, you will find the skeleton of your husband at the bottom floor of the Demon Locking Tower. After you learn how to fly with a sword, you can enter the Demon Locking Tower. You can go to the seventh floor and give the remains to the Ice Crystal Girl, and you will be rewarded with fifty thousand coins.

Corpse pieces: (1) Spirit Snake Slough*1 Half-Human Snake Star Sinking Earthquake (Sedum Level 50 acquisition probability 20 selling price 4500)

Cuprite Spirit Snake Slough— —Zixuan——Menghuatian Snake Crown Waterproof 48 Speed ??1

(2) Soul-catching Eye*2 Five Emperors' Head Sword Overturning the Country Silver Wave Bullet (Sedum Level 58 acquisition probability 20 selling price 4500)

Cuprite soul-catching eye - all accessories - Tianming Bao ring, lightning protection 10, energy recovery 15%

This is the strategy I am looking for, you should understand it, right? It should be considered easy... I feel sad for Cao Hai and Shen Mo