Here is the full list of all 15 Below Sunshade achievements.
Find the Guardian Blade
Unlock The Harmony Ending
Save The Heart
Corrupt The Heart
Become The Champion
Save Fang
Leave With Naipei
Help Tulip
Escape The Island
Reach The Mountain Top
Become Friends With Idrune
Charge The Artifacts
Share A Deep Bond
Help Galan
Craft Ten Camp Buildings