Chinese-server data. English names and effects are provisional; untranslated details remain in Chinese.
Prayer stone
Flag Prayer Stone
旗帜祷石
BlueStrengthExtra effect · Strength Attunement reaches grade A
Source: Random drop
Prayer stone effects
During a team rest, if the squad has a Strength crewmate, squad members gain 斗志昂扬, increasing Attack by 4% until the next team rest.
Extra effect
Strength Attunement reaches grade A
When Strength 感召力 reaches C, gain 斗志昂扬, increasing Attack by 6%.
Acquisition source
Random drop
Recorded source: Random drop.
Source: 遗忘之海 · 祷石记录器 (Chinese)Lore
Item story
The pattern inside looks like a flag about to unfurl in the wind.