Here's the basic data that pertains to this character.
Beyond that, there's not a lot to tell (yet) about Kratorr. He only appears in one panel (full page) of Astro City Comics. That is both the beauty and the frustration of this comic series. A lot of detail and design goes into the background of the stories. Some of it is just throw away. Use it for one panel, maybe make some reference to previous adventures (like here with Augustus Furst commenting that he has defeated Kratorr nine or ten times in past) and then move on with the main actions of the current storyline.
Yet here is this visually intriguing villain, in need of further information to help fill out this entry on the Herocopia pages. So the frustration becomes what to do to add enough text content to make clicking to this page worth the effort. Frustration also mounts because you really want to read about some of the past battles between Kratorr and Augustus, and maybe find out more about the origin of Kratorr and his minions.
Alas, none of that is available at present. Perhaps never. So for now, contentment must come from just admiring the stunning picture, the great pose and the expert crafts of the creative team tickling your imagination as you ponder all the cool things that might be part of this wonderful character and his decades long interactions with the First Family.
Using lunar(?) geological material, he possesses the ability to concoct servitors, smaller sized humanoid forms similar in appearance to himself.