Ofuda (御札 or お札 o-fuda, a charm) are inscribed strips of paper or other material used within the Shinto religion as amulets or talismans for purification, exorcism, or protection. It is common for ofuda in manga or anime to have other abilities, such as timed explosion ("paper bombs"). The use of ofuda is not uncommon in the Len'en Project; Tsurubami Senri is covered in ofuda and uses ofuda as danmaku in one of their spell cards, and Lumen Celeritas has two ofuda on their head and later all over. Souko Shirami also has an ofuda on their hat to repel demons.
Tsurubami Senri covered in ofuda.
Tsurubami using ofuda in one of their spell cards: Mysterious Card "Monochrome Bivalence".
Tsurubami using ofuda in one of their spell cards: Whirlpool Card "Spiral Galaxy Barrier".
Lumen Celeritas having two ofuda on their head
An ofuda on Souko Shirami's hat