Empire containing other empires?

[grisamentum]

My question was about same tier empires but both with same de jure territories (or at least some of them). It'd be historically plausible to have Latin Empire claims on whole ERE (on the other hand they were usurpers).

Yeah, no. As far as I know you definitely can't have two de jure empires that share the same land.

 

[takedown47]

I think the levels should go:
Emperor-Empire
High King-Kingdom
King-Kingdom
Grand Duke-Grand Duchy
Duke-Duchy
Viscount-County
Count-County
Baron-Barony
Lord-Manor

I wish that was possible but there a hard coded limits built into the game engine

 

[Arko]

I wish that was possible but there a hard coded limits built into the game engine

in terms of game mechanics, the hierarchical pyramidal 5 tier system works fine (even if somewhat historically inaccurate because it was not so linear and homogene).
Additional fictive tiers can be added at will for flavour if needed. Some turnarounds can be found to create differenciation (minor title with monthly prestige tied to specific titles and such)