In Jain cosmology, there is no chakravarti king ruling a narak (hell). Chakravarti are the universal sovereigns who, in the earthly realm (Bharat/Kshetra, Jambudweep), rule over the world of living beings. The naraks are realms of punishment within the cosmic structure, but they are not governed by chakravarti monarchs. So, there is no “chakravarti of the 7th narak.”

If you’d like, I can point you to specific Jain scriptures or passages that describe the narak lok and the role of chakravarti on earth.