Answer

The sister of Sthulibhadra was Yaksha — also known in Jain tradition as Sadhvi Yaksha.

Explanation

Sthulibhadra was a highly respected Jain monk, remembered for his deep knowledge, restraint, and spiritual discipline. His sister Yaksha also accepted Jain renunciation and became a sadhvi.

Spiritual Understanding

The lives of Sthulibhadra and Sadhvi Yaksha show the Jain ideal of leaving worldly attachment and walking the path of samyam — self-control, renunciation, and spiritual purification.