Honestly this was to be expected. Demon Rank in the Netherworld carries weight and seems based on an individual Demon's power, influence, and achievements. Sadly, the most Iruma has going for him at this moment (that's not borrowed btw) is his achievements, which unfortunately isn't too well known to the masses with the exception of a few. In short, he still has much room to grow and improve himself. Of course, that's my own opinion, and who knows the next chapter may just throw a curve ball that shatters my thought process.