Answer

In Jain tradition, the sister of Skandhak Kumar is commonly known as Sudarshanā.

Explanation

Skandhak Kumar is remembered in Jain stories for his deep vairāgya and spiritual inclination. His sister Sudarshanā is associated with his life-story in traditional Jain narratives.

Takeaway

Sudarshanā is regarded as the sister of Skandhak Kumar in Jain tradition.