Spell cards (スペル牌 Superu fuda) appear to play an important role in casting powerful character-specific magic in the Len'en Project. During a spell card trance, the user's offensive and defensive capabilities appear to increase greatly. In some cases, the user becomes completely invincible for the duration of the trance. However, the user may only cast the spell that was specified by the spell card until the trance ends, limiting its overall usefulness.
Game Spell Cards
In the Len'en Project games, spell cards manifest themselves in a few ways. In the shoot 'em ups, spell cards primarily act as a source of danmaku by enemy characters as they shoot a pattern or sequence of bullets at the player character, who tries to dodge them. They each have a name of some sort that's required, and the names notoriously use quotation marks (「example」). The spell cards contain health bars as usual that need to be emptied in order to defeat the spell card. These are usually used by bosses and midbosses on stages and have never been used by a stage enemy. As well, they are used as life-saving "bombs" by the player characters to become temporarily invincible and cancel out bullets.
Spell Card System
The first character to use the system on-screen was Kurohebi. The system is based on the spell card system from the Touhou Project . In the story of the Len'en Project, however, spell cards have been stated to have different origins than in Gensokyo . The exact details are unknown, but they were apparently invented by the Senri Shrine's yet-unnamed second generation priest. Unlike Touhou though, there are technically no spell card rules. Because Mugenri is a dangerous place to live, there is a risk of death, according to the games' manuals.