Which Version Of Boo

[Let's Go Fearless!]

That destroyed hundreds of planets 5 million years ago? Was it Fatty or Kiddy?

 

[Captain Cadaver]

Quick and rampant destruction is definitely more in line with Pure Boo's work, not to mention the anime making it clear Shin was referring to Pure Boo. Even manga-wise, he made this statement along with saying how the Kaioshin were killed, implying he was definitely talking about Pure Boo. Fat Boo likes to destroy things as well, but he usually takes his time to play around or see what a planet has to offer rather than Pure Boo's method of doing things quickly and moving on to the next world.

 

[Let's Go Fearless!]

I don't know if this is correct but didn't Pure Boo went to attack the Kaioshins immediately which mean that hr barely had a time to destroy the other planets?

 

[Captain Cadaver]

Shin stated that those hundreds of planets were wiped out in a few years, but never gives a timeframe of when Boo attacked the Kaioshin and makes it apparent Bibidi sealed Boo more than once as it was his way of having a break from Boo's ferocity. Nothing really contradicts the anime's interpretation of events, either.

 

[GreatSaiyaman123]

On top of what CC said, Kaioshin also described Boo as a being who lacks emotion and reason, both things Fat Boo have. So he's definitely talking about Pure Boo.