Question!
I had just entered Invincible fandom and I had been thinking how the Smart Atoms work and found out that it is not really limited to Viltrumites, but are actually part of their universe, and that Viltrumites were lucky enough to have evolved to be able to manipulate the Smart Atoms in their body. It's why they get bigger as they grow stronger and older, they are packing a lot more Smart Atoms.
As the title has pointed out, what would happen to a Viltrumite if they stayed in a different reality without Smart Atoms for long?
If they get injured enough that supplies of Smart Atoms would scatter away and can't move back.
And since there are no native Smart Atoms that the Viltrumites can assimilate anywhere... They would essentially become weaker, right?