38 πεπεισμαι γαρ οτι ουτε θανατος ουτε ζωη ουτε αγγελοι ουτε αρχαι ουτε ενεστωτα ουτε μελλοντα ουτε δυναμεις
38 For I am convinced that neither death nor life, neither angels nor demons,[a] neither the present nor the future, nor any powers,
[a] or heavenly rulers (NIV)
The world I bolded is archai. Etymologically, it shares the same root with words like archons, archangel, etc. Archai must be rulers of some sort, but Paul juxtaposes it with αγγελοι (a[n]ggeloi) which could be either angels or messengers. The context that makes the most sense is the NIV translation: angels or demons. So already, we have a precedent for “rulers = demons”. Paul never uses any word derived from “arch-” for people or entities he likes.
1 Corinthians 2
6 σοφιαν δε λαλουμεν εν τοις τελειοις σοφιαν δε ου του αιωνος τουτου ουδε των αρχοντων του αιωνος τουτου των καταργουμενων
6 We do, however, speak a message of wisdom among the mature, but not the wisdom of this age or of the rulers of this age, who are coming to nothing.
8 ην ουδεις των αρχοντων του αιωνος τουτου εγνωκεν ει γαρ εγνωσαν ουκ αν τον κυριον της δοξης εσταυρωσαν
8 None of the rulers of this age understood it, for if they had, they would not have crucified the Lord of glory.
Again, Paul is using “arch-” meaning people or entities he doesn’t like.
1 και υμας οντας νεκρους τοις παραπτωμασιν και ταις αμαρτιαις υμων
2 εν αις ποτε περιεπατησατε κατα τον αιωνα του κοσμου τουτου κατα τον αρχοντα της εξουσιας του αερος του πνευματος του νυν ενεργουντος εν τοις υιοις της απειθειας
1As for you, you were dead in your transgressions and failures (*or sins)
2 in which you used to live when you followed the ways of this world and of the ruler of the kingdom of the air, the spirit who is now at work in [the sons] of disobedience.
The ruler (archonta) of the air/heavenly realm. An entity that Paul doesn’t like, who he says is causing some people to sin. I underlined a crucial word: πνευματος::pnevmatos which means spirit-like. So some sort of heavenly spirit, a ruler of some sort, is causing people in his church to sin.
10 ινα γνωρισθη νυν ταις αρχαις και ταις εξουσιαις εν τοις επ’ ουρανιοις δια της εκκλησιας η πολυποικιλος σοφια του θεου
10 [God’s] intent was that now, through the church, the manifold wisdom of God should be made known to the rulers and authorities in the heavenly realms
The rulers (or demons i.e. “archias” from Rom 8:38) of the heavenly realm (επουρανιοις, I’ve written it as επ’ ουρανιοις – “over-sky”) are ignorant of god’s assembly (or church).
12 οτι ουκ εστιν ημιν η παλη προς αιμα και σαρκα αλλα προς τας αρχας προς τας εξουσιας προς τους κοσμοκρατορας του σκοτους τουτου προς τα πνευματικα της πονηριας εν τοις επ’ ουρανιοις
12 For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms
It seems as though Paul sees these archons as some sort of heavenly, spiritual beings that Paul sees as working against the church. Maybe the Gnostics were right – the archons:
In late antiquity the term archon was used in Gnosticism to refer to several servants of the Demiurge, the “creator god” that stood between the human race and a transcendent God that could only be reached through gnosis. In this context they have the role of the angels and demons of the Old Testament. They give their name to the sect called Archontics.
Paul uses the term “rulers of this age” in a derogatory way (1 Cor 2:6,8 above). The same way that he use the term “god of this age” (2 Cor 4:4 – θεος του αιωνος) in a derogatory way. It seems as though Marcion or the Gnostics did have a reason for their beliefs. The rulers of this age were working for the god of this age – the Demiurge (δημιουργος::demiourgos – literally craftsman or creator) and his demons. For Paul, Jesus and his Father came to disrupt their plans.