Chinese-server data. English names and effects are provisional; untranslated details remain in Chinese.
Prayer stone
Defense Prayer Stone
防守祷石
PurpleConstitutionExtra effect · Constitution Attunement reaches grade B
Source: Random drop
Prayer stone effects
When an allied unit is attacked, there is a 50% chance to gain a shield equal to 10% of its HP for 2 turns.
Extra effect
Constitution Attunement reaches grade B
Gain an additional shield equal to 5% of its HP.
Acquisition source
Random drop
Recorded source: Random drop.
Source: 遗忘之海 · 祷石记录器 (Chinese)Lore
Item story
The shield pattern contracts now and then like a beating heart. Lighthouse sentries at sea are said to have stayed awake for three nights by holding it on watch.