In the manga Shiki was a member of the Tao clan who survived the war against Chronos 25 years ago. Although young at the time, he expressed interest in participating in the conflict if he had been older. As a Master-Level Taoshi, Shiki manipulated his Chi and used insect summoning as his primary form of offense. His Tao Power was known as "Insect." Additionally, he mastered the use of ink seals, which allowed him to manipulate his Ki in various ways, including creating a seal sword and an energy blast.
In the anime, Shiki's backstory is not revealed, and he did not fight Train or play a major role in the Apostles of The Stars. However, he was part of an elite team summoned by Mason to execute the Eden project. Despite this, he often used his insects to gather information for Creed. Shiki later fought Anubis.