Why does Bermuda always address characters as -kun? In the manga of Katekyo Hitman Reborn! (also commonly just "Reborn!" for obvious reasons) after the future and Shimon Arc ends, the Arcabaleno Arc begins and reveals that:


   Bermuda, the arcobaleno of the eighth element of night, bargains with Reborn in Chapter 384-ish to take his life for future generations and use his life to kill Checker Face. 


While reading it, I noticed Bermuda calls all characters "-kun"! Since it's obviously a term more for guys, and yet it was used on Chrome and weaker players like Lal Mirch etc., I thought it was a little strange. I don't think it's a translation error either - since 「―くん」is pretty obviously "-kun".

Is there any explanation for this? Is it something to do with his personality?
In this case I believe Bermuda is looking down on all the characters as if they were his subordinates or just addressing in an endearing sense (he is way older than them).

In company or school situations in Japan "-kun" is by superiors when addressing subordinates of both genders. Alternatively "-kun" might also be used as a term of endearment towards the (younger) male characters (similar to "-chan" with females).