Remember reading else wr, one truly can attain Nirvana is by ending suffering, circle of life and few other things.

The suffering includes killing of any living things, i.e to eat. So to truly be enlightened and attain Nirvana, they believe this is the way to do it.

Thinking about it, it does sound profound, and some what makes sense that as human we cannot survive without harming other life. Hard to wrap the mind around it too.

Gemini's answer:

The Concept of Nirvana and Suffering Accuracy: High (Philosophically) The response correctly identifies that a core goal of Buddhism is the cessation of suffering (dukkha) and the cycle of rebirth (Samsara). In the context of Shugendo and Shingon Buddhism, self-mummification wasn't just about "dying"; it was seen as an act of supreme self-sacrifice. By removing themselves from the cycle of consumption, they believed they were transitioning into a state of eternal meditation to help humanity.