After concealing her humans, Tsunami cast herself adrift. During the
long time of Tsunami's drifting, humanity fractured into different
groups. They muddled along despite the death of their great empire, and
some founded their own states. Empires came and went, and great pirate
guilds fought each other for galactic control. Some were quite advanced
and powerful, and the Jurai guild discovered Tsunami. By recovering the
ship and its secret, the Jurai had selected themselves for Tsunami's
purpose. 

The first emperor's sister was herself Masaki's avatar, indeed was so
named because of the power of that link. The real Masaki now existed
within a pocket dimension created by Tsunami, and these avatars could
not live for very long. A mere thirty years. But in her short time she
helped find her "male" or Yang counterpart that wielded this power. A
scene in TTM 1 connects this to the Yi myth. Upon one of the young
Azusa's visits to Mitsuki, we are told of a full moon upon his
departure. On another occasion he confronts Seto, with a full moon
shining behind him. Mitsuki is another one of Masaki's "echoes", and is
being used to test Azusa. The power of Washu is the antithesis of
Tsunami's, and each human being contains this power in their soul,
since she is the Goddess of Life. The emergence of the moon from
darkness denotes that the person in question has this power in adequate
purity, and more so than the previous one. Each increase in power
brings Tsunami one step closer to resurrecting her sister without the
dark taint of Habuki. Eventually the entire treasure would become
embodied in one king, and their progeny would be the restored Washu.

To assist the Jurai Tsunami used her sister's energy to create the
Royal Trees. Each tree contained part of Washu's power, and would exist
in symbiosis with persons that reciprocated this power. Each possessed
consciousness derived from Washu much like the Ten Suns, even though
the Sun Goddess was too far gone to be actively engaged.  For reasons
that will not be explored here, the trees would lose their power if
rooted in Earth, so their power was maintained by immersion in water
(Tsunami's element) that would give balance.  Each generation of tree
divided into levels of power they shared with their symbiote. The lower
the generation, the more powerful the tree. Lower gen trees could
create three LHWs, and higher ones just one LHW. Only "Tsunami"
herself, the ship that the last sun slept within, would create the full
ten LHWs. 

Three gems existed at the center of this last sun, and from these
Masters were generated the gems within the core of each tree. These
three were the center of the entire system, and were the "treasure"
mentioned in OVA 5 by Yosho. Eventually these would be the reward of
the Final King, and the last Jurai generation would be born, and Washu
resurrected. Even the founding emperor of Jurai could not control them,
but then he was too much like Tsunami, and it was from his basis, and
from his mysterious stepsister Seto that the basis of what would become
the Jurai royal families were generated.

But Tsunami and Tokimi were divided because they could only see one
side of the same problem, and that half understanding was the flaw in
both of their plans.