There are 12 universes each have their own God of Destruction Beerus isnt said to be the weakest but that in some of the univereses there are beings more powerful then He and Goku ... Maybe Whis and his kid are all from a single universe who knows lol ....I agree tho Omega is no match for Beerus
and by 12 - the story just goes with 12 universes ... or zones how i like to call them ... but if a theory of an infinite universe might exist ... wow just imagine the fighters and gods there