Ophiuchus is a guardian gargoyle and the Infernal Source's thirteenth member of the Malebranche. It is found in the Vestibule of Futility, the uppermost level of the Infernal Source. Ophiuchus greets the player on their first visit to the Infernal Source and serves as the start of the Contract Claws mystery, wherein the player must free the guardians of their contracts.
- Ophiuchus is one of thirteen constellations that cross the ecliptic and was once a part of the Babylonian and ancient Greek zodiacs, though it has not been used in Western astrology for over 2,000 years. It is sometimes called the "13th sign of the zodiac".