From Fate/Grand Order Wiki
"A beautiful mantle, suitable to be worn by a hero. Obtained during "Halloween Comeback! Super☆Ghouls 'n Pumpkins - The Seeds of Adventure."
It's name is Stardian.
If used during Super☆Ghouls 'n Pumpkins quests, NP Strength for all allies will be increased by 50%."
Used for Enhancement by