On the nature of yuvans, kuva, and continuity
to explain continuity we need to understand the 4 parts that are essential to its ceremony
kuva,yuvan,yuvan theaters, and the process
kuva is a sacred liquid that, in general, can mold the essence of the being that it is objected to
Examples of it being used are
1-kuva liches are made by remolding a diseased and decaying grineer subject into a powerful kuva-infused semi-immortal elite soldier
2-in continuity which we will discuss further in this thread
3-voruna's usage of kuva to fuse the bodies of her frame and her 4 dead loyal companions
4-the revival of ordan karris and his subsequent glassing into ordis
It is to be noted that according to grandmother, there are 2 types of kuva, those being blue and red kuva
Blue being a temporary takeover (lasting a few hours to a day with the orokin that consumed going back to their original body)
and red being a permanent one
Yuvans are the few chosen to have their essence taken over by the orokin; it is considered a great honor in orokin society to be selected as one, a well-known source for yuvans are colonies of Mars where children are taken (unwillingly, clearly) from their families to be paraded in front of dying orokin and selected as an orokin's next body
We should also note that the grey skin color an orokin presents isn't natural but is probably a result of further body modifications (similar to the extension of one arm)
The Yuvan Theater is where most of the yuvan ceremonies are committed
Some well-known theaters are the two theaters on Lua (yuvarium and Circulus) and the one atop a mountain on Earth (seen in The War Within), with the theaters on Lua being the most suitable as they are closest to the void's influence (judged by the void mirror at the center of voruna hall)
We must address that continuity doesn't require a specific location to occur, just the place itself must have a strong void connection
Now, the process itself isn't as complicated as it may seem
First, an orokin consumes the sacred kuva, then begins to connect to the mind of the chosen yuvan, bit by bit, they begin to weaken the resolve of the host's mind until they can simply eradicate it and replace their innocent essence with theirs