| Kurt | Austin | Head of NUMA's special projects. |
| Kenzo | Fujihara | A scientist. |
| Rudi | Gunn | The NUMA's assistant director. |
| Walter | Han | Wen Li's proxy. An industrialist. |
| Zhang | Heng | A Chinese scholar. |
| Hideki | Kashimora | The man in charge of Sento. |
| Priya | Kashmir | The multidisciplinary expert. |
| Wen | Li | One of the most powerful men in China. |
| Goro | Masamune | Japan's greatest swordsmith. |
| Sengo | Muramasa | Alleged Masamune's apprentice. A great swordsmith. |
| Superintendent | Nagano | The high-ranking Japanese police. |
| James | Sandecker | Former Head of Numa. The U.S. Vice President. |
| Yoshiro | Shimezu | The Samurai Warrior. |
| Gamay | Trout | A marine biologist. Paul's wife. |
| Paul | Trout | NUMA's lead geologist. |
| Joe | Zavala | Kurt's right-hand man. |
| General | Zhang | Head of the ministry for state security. |
| Gao | Zhin | Hank's chief engineer. Aka: Mr. Gao. |
| Akiko | | Kenzo's sergeant at arms. |
| Kasimoto | | The Shogun. |
| NUMA | | National Marine Underwater Agency. |
| Sento | | The illegal gambling establishment. |
| Ushi-Oni | | The former Yakuza assassin. Walter Hank's associate. |
| Vala | | A Norwegian geologist. |
