Considering only the body is real; whereas that may be true it does not prohibit the idea that the body could be house to or become the soul.

Inclined to develop soul, an immortal form of life, killing has to stop. This is almost impossible as an animal, but meditating on the problem by being vegan and see what obstacles there are to overcome.

Just because it seems impossible, doesn't mean the to attempt is fruitless. Bodies or forms that are parts of the universe, exist only within the confines of the material, and the unbounded will.

The will of the mind is limited by the unsustainability of the body, so immortal life cannot be of the body and hence not constrained by it's matter, hence the will can be unbounded.

Desire for immortality is fraught with the will of action in time. For whilst immortality must exist in space, desire is limited by the mind. To unchain the mind from the body is best started by unchaining the body from the concious, everyday mind, or mental processes.

Adopting regimes like religion, sustainability may help to control the chains and yet will also enforce them to discipline. The step of discipline only works in extreme, where it can be seen to be an infinite bond to the will.

Acknowledging will and desire without expectation is a key to immortality. Removing expectation is a step through the door.