>>10697435>>10697476There are some pretty fundamentally recognized power-tiers in 40k. Greater Daemons and Daemon princes are way, way above rank and file marines.
on a really basic level that only really covers imperials and chaos:
Regular mortals(guardsmen/cultists)>Lesser demons> Astartes >> Custodes(and arguably GreyKnights) >>> Greater Daemons and Princes >> Primarchs > Daemon Primarchs
I din't even try to slot in mortal specialists like assassins, Mechanicum, psychically gifted Inquisitors, or imperial saints like Celestine/Sanguinor who are basically loyalist greater daemons. There's also the legion of the damned, which are undead warp-astartes that come and go with the warp wherever they are needed, they would be the loyalist lesser daemons.
Unless you are a named space marine hero with incredible feats(and plot armor) you are not going to be punching into the Daemon-prince and greater daemon categories. Belakor is a pretty special Daemon prince too, the first one to ever be undivided(gifted power by all 4 chaos gods).