There is only one category of marginal living entities know as the individual jiva-souls however, the individual jiva-souls can exist in "two different ways", both considered to be eternal, but only while the individual jiva-soul is in that position.

Both the spiritual world, which is 75% of the Spiritual Sky, and the material world, which is 25% of the Spiritual Sky, are eternal. 

The individual jiva-souls who are naturally and originally nitya-siddha in the spiritual world, can also be materially conditioned (by choice) as nitya-baddha in the temporary material world of repeated birth and death.

Also the individual jiva-souls can eventually be further conditioned under the heading of nitya-baddha, by "artificially appearing" as a dormant (inactive) bodiless "spark" in the impersonal brahmajyoti after becoming frustrated with the suffering experienced within the temporary material world's suffering of repeated birth and death.

This means the individual jiva-soul as nitya-baddha, is temporarily conditioned as "active" in material world's cycle of repeated birth and death, or "inactive" (dormant) in the impersonal brahmajyoti.

Nitya-siddha means being eternally liberated, which is the individual jiva-souls natural un-conditioned state in the spiritual world's of the eternal Vaikuntha planets and. 

Srila Prabhupada – "The answer to your question about the marginal energy is that the individual jiva-soul is always called the marginal energy whether he is in the spiritual world or in the material world." (Letter to Rayarama, Dec 2, 1968)

This point is emphasised here to make it clear only one kind of jiva-soul exists and due to having free will, can choose to be either nitya-siddha or nitya-baddha. 

The eternal individual jiva-souls can be either (by choice) nitya-siddha (liberated in the spiritual world if they choose which can be eternally) or nitya-baddha (conditioned in the material world, or impersonal brahmajyoti if they choose however, both these conditions are temporary)

Srila Prabhupada - "In the broader sense everyone comes from Krsnaloka. When one forgets Krsna he is conditioned (nitya-baddha), when one remembers Krsna he is liberated nitya-siddha." (Letter to Mukunda, June 10, 1969)

Srila Prabhupada - "There are two kinds of marginal living entities: nitya-siddha (un-conditioned in the spiritual world) and nitya-baddha (conditioned in the active material world, or inactive in the impersonal brahmajyoti). The actual constitutional position of every marginal living entity is nitya-siddha." (CC, lecture, July 13, 1976) 

Srila Prabhupada - "By following the rules and regulations and instructions of the spiritual master, he can become AGAIN nitya-sillddha. So the Krsna consciousness movement is to make the nitya-baddhas AGAIN nitya-siddha." (New York City Temple Lecture CC, July 13, 1976)

Srila Prabhupada - "So the Krsna consciousness movement is to make the nitya-baddhas AGAIN nitya-siddha, to bring them to their original position. It is a difficult task." (London lecture BG, 13-14, July 14, 1973)**