An Ultraverse is the highest space between a Megaverse and the Omniverse. Ultraverses contain very large parts of the Archverse chain. In this way, it can be seen as a large container of archverses, or a container of the metric -verse chain. (Gigaverse, Teraverse, etc)
Ultraverses can have different properties just like their lower counterparts(universe, multiverse, etc) since they are contained by a higher verse, commonly only a larger archverse.