In Jain Dharma, there isn’t a person or god who “decides” your next life. Rebirth is determined by karma—the exact mix and strength of accumulated karmic particles (punya, papa, and other karma) that cling to the soul due to thoughts, speech, and actions. The soul’s own karmic ledger shapes what form it takes in the next birth, as well as the realm (human, animal, insect, heavenly beings, etc.). So the question isn’t decided by someone else; it unfolds according to the law of karma and the soul’s ongoing behavior. Both Digambar and Shwetambar traditions affirm this karmic mechanism, though they may discuss details of karma and rebirth in slightly different ways.

If you’d like, I can explain how different kinds of karma influence rebirth (e.g., what kinds of actions tend to lead to difficult births) in simple terms.