Here is the full list of all 14 The Charming Empire achievements.
Completed the Normal ending of Soshi Amazaki
Completed the characters' Normal endings
Completed the Normal end and Happy ending of all characters
Completed the Normal ending of Koichiro Sera
Completed the Normal ending of Toki Tanba
Completed the Normal ending of Kei Yoshimi
Completed the Normal ending of Kagemitsu Togawa
Completed the Happy ending of Kagemitsu Togawa
Completed the characters' happy endings
Completed the Happy ending of Kei Yoshimine
Completed the Happy ending of Koichiro Sera
Completed the Happy ending of Soshi Amazaki
Completed the Happy ending of Toki Tanba
Completed the a prologue