The Coffin of Eternity is used to keep someone in a complete stasis, and blocks out everything from the outside.
It was first seen when it was used on Hong'er to keep her in stasis keep the devilish poison inside of her from killing her. It was taken by Yun Che after he saved Hong'er. 
Later when Yun Che told his parents that he was their biological son, he ended up showing the body of Yun Canghai, who when Yun Che had taken the Coffin of Eternity, put his body inside of it.
It has the appearance of a crystal coffin.
Known Uses Edit
- When Hong'er was infected with a devilish poison she was sealed inside the Coffin until the Sky Poison Pearl was found
- Yun Che put Yun Canghai's body inside of it after he obtained the Coffin.