A Gigaverse is a huge "complex" of various Megaverses. All Megaverses within a Gigaverse have less connections and are further away than Multiverses in a Megaverse and Universes in a Multiverse, which is why -verses leveled inbetween the Gigaverse and Omniverse start to lose any signifcant meaning. Gigaverses are the last level of unofficial Archverses before becoming unstable afterwards.
The high Kardashev Scale jump is because of the low density of Megaverses. For reference, a Megaverse scores a 9 on the Kardeshev scale.
Gigaverses aren't actually part of the normal scale of Multiverses, but they still play a big purpose in existence. Due to the lack of any significant meaning, the Gigaverse is the start of the Archverse chain.
It is hard to describe how Megaverses are arranged in a Gigaverse, due to a lack of any significant meaning at this point. This leads into a unobserved theory that any meaningless Archverse is patternless and chaotic at these scales.
But, the grey void here from the picture shown that it is a really dense void made of nonexistence, making civilizations hard to get out of a Megaverse. Megaverses within are represented as black dots, which are immensely colder than Absolute Zero, making it abstractly cold. The fog shown that it has been cool down from "glitchy" radiation, but still has hyperradiation that it could erase people from existence. It is theorized that it is made of hyper-atoms acting like dark matter right there. These reasons are why the entire structure of a Gigaverse is hardly describable.
Megaverses within a Gigaverse are invisibly linked with each other, to carry out Lawium for a fix to law manipulations. It is hypothesized that when Megaverses move farther away, they create a really unstable Megaverse; leading to a horrifying, potential factor to Gigaverse's unstable structure as an apocalypse.
Unfortunately, they are really slowly decaying due to "cold" hyper-radiation. That decay leads into a chance that a sub-Megaversal portion stops working, and thus propelling lower Archverses outwards. These verses will then become imaginary with no matter information preserved. Megaversal civilizations had to traverse through Gigaverses and even Teraverses in order to harvest Superfabric and protect with a Metabubble against these 2 horrifying factors.
Typically, Gigaverses start out as a glitchy mess. However, this glitchy mess slowly unravels into multiple Inforiums which expand differently based on resources and carry out slightly different instructions, forming Megaverses.
Gigaverses can still rarely have a glitchy mess inside of them at this point, making them harvestable for Lawium, a very strong substance for matter information. There is a tremendous low chance that Glitchonicite appears here afterwards, a important substance for reality shifting throughout Archverses whilst being a glitch in a "reality."