The Flower that Blooms on the Dead

Astral is approached by Diana, the president of the magic items provision corporation Trismegistus, to find a special flower that is seeded within a human body and blooms after their death. As the mission was originally taken by Itsuki's father, Itsuki accepts. However, they are attacked by Li Cheng Chen, a magician that can raise the dead.

Synopsis excerpt via Kitsu.