The weird sci fi guys ?

So I'm new to the Hellboy comics, reading through omnibus 1 and theres this moment when Rasputin is freeing the Ogru Jahad and we suddenly cut to this weird alternate dimension of sci fi guys yelling about how "Releasing them could cause untold destruction across the multiverse".

Now I realise Hellboy likes to mash genres alot, albeit usually sticking to a mixture of pulp/horror but these guys seemed REALLY out of left field. Do they ever turn up again ?

Yeah! On the second omnibus you will found a bit more about these creatures - and 23 years after Seed of Destruction was published they released The Visitor, one of the most peculiar stories on the Mignolaverse focused on this theme.