Kz-sama
This is Kawaguchi Hidetoshi. This is my humble answer to the question.
Regarding the existence of “spirits,” as Mr. Tomoyasu Somekawa also said, in Buddhism, we are basically in the position of “ignoring” (there is no benefit in discussing them), but if we dare to state it as a close being, we can think of a “meaning body” (meaning body), where minute consciousness and minute mind, which are not affected by the rough body or rough consciousness we have now, can show a shape like a shadow of the body.
Of course, even if there is such a thing as “intention,” it is not something that is permanent and eternal, but it will be “auspicious” where it is dependent on others, for example, due to causation (cause and condition).
In any case, in the reincarnating continuum of mind (mental inheritance) (of course, it is something that is auspicious when emptied), it is possible to move towards a good destination by adjusting good causes and relationships.
In order to move towards that good destination, of course, in the case of Buddhism, it is necessary to learn and practice teachings to adjust the causal relationships leading to enlightenment and nirvana.
Even if we have “spirits” as we imagine them or not, there is no change in the fact that mental inheritance continues to be reincarnated depending on cause and effect even after death.
Therefore, I think the intention of Shakyamuni is that discussions about spirits are futile, and that it is the intention of Shakyamuni to work firmly on methods (Buddhism) to adjust good causes and relationships anyway.
If released, it becomes “nothing”...
In the case of Mahayana Buddhism, enlightenment is attained based on several vows, such as the Bodhisattva commandment, etc., so basically, “Dharma” and “color body” (revenge/response) as the body of the Buddha and Nyorai can be obtained by broadly dividing them towards “the salvation of all sentient beings,” which are always present in that vow.
So, at least, I don't think it will become complete “nothing” until everyone is saved. (Of course, even if all are saved, there is no denying the possibility that the corporation remains.)
Kawaguchi Hidetoshi Gassho