The Longest Promise

The Longest Promise, is a 2023 Chinese television series starring Xiao Zhan and Ren Min. It is based on the xianxia romance novel Zhu Yan by Cang Yue. It is the prequel of the 2021 series Mirror: A Tale of Twin Cities. The series started airing on Tencent Video and WeTV on July 2, 2023, and concluded its run of 40 episodes on July 20, 2023.

Synopsis
Shi Ying is the crown prince of Kongsang. However, after being framed by the imperial consort Qiu Shui, he had to fake his death to escape from the palace. He was sent to Jiuyi mountain to cultivate. Later, he meets Zhu Yan, a princess of Chi Yi clan, who becomes his disciple.

Main

 * Xiao Zhan as Shi Ying
 * Jian Yuxi as young Shi Ying
 * Former crown prince of Kongsang and priest of grand preceptor


 * Ren Min as Zhu Yan
 * Li Xiyuan as young Zhu Yan
 * Princess of Chi Yi clan and Shi Ying's disciple

Supporting
Kongsang Royal Family
 * Zeng Li as Bai Yan
 * Empress of Kongsang, Shi Ying's mother

Jiuyi Mountain White Clan Chi Yi Clan Merfolk Clan Others
 * He Shengming as Emperor Beimian
 * Ye Shengjia as Shi Yu; Shi Ying's younger half-brother
 * Chen Zijan as Qing Yun, an imperial consort and Shi Yu's mother
 * Chen Xinyu as Qiu Shui; a merfolk and imperial consort
 * Han Dong as High Priest of Grand Preceptor / Da Si Ming
 * Li Mingde as Chong Ming, a divine bird of Jiuyi mountain
 * Wang Churan as Bai Xuelu
 * Lu Yuxiao as Bai Xueying
 * Zhang Lei as Bai Jing'an, King of White clan
 * Fan Linfeng as Bai Fenglin
 * Guo Jun as Zhu Gaozhao; King of Chi Yi clan and Zhu Yan's father
 * Yang Mingna as Zhu Changxiang; wife of Zhu Gaozhao and Zhu Yan's mother
 * Ding Jie as Yu Fei, Zhu Yan's maid
 * Fang Yilun as Zhi Yuan
 * Wang Ziqi as Qing Gang, leader of Shadow Warriors
 * Yu Xuanchen as Lan Xiqiao
 * Gallen Lo as Emperor Xing Zun, founder of Kongsang continent
 * Zhang Shuangli as Reverend Xuan Zhen
 * Ruan Shengwen as Qing Dongfang, King of Azure clan
 * Wang Yiyao as Ru Yi

Production
The filming of "The Longest Promise" started in Hengdian World Studios in March 2021. The shooting of whole drama was completed in August 2021. On March 29, 2021, the official Weibo of "The Longest Promise" announced the lineup and released the posters of the main protagonists.