@Renard (Imo) From the looks of it, It didn't really matter at that point whether or not Phos took the eye for himself because both would have been win-win scenarios for Aechmea. It is possible that he wanted the power to pray for himself, considering he is a messed up individual much like the rest of the sector of souls that couldn't be purged and became the current Lunarian society. But is also painfully obvious that he led Phos to this outcome. He wanted to make a "human" so they would finally meet their end, and now he has it in Phos.
However I don't think he was being dishonest about wanting to die along his people. Their existences are horrible, as pointed by Aechmea himself, even If they don't look like it. They are basically tired of immortality, and were rotten to their cores. I do think, however, that Aechmea is extremely opportunistic, and I have no doubts he would have fucked it up for everyone else If he had the chance (which.... was already proven as seen by him KNOWING Adamant's pray would kill every single life form descended from humans)
@SupremeEdgelord Impossible. Him and his bimbo ass are far beyond salvation at this point. The only thing left is...
prayer.