What happened to her majesty´s host and to Thetis?

The young Julian Solo went back to his normal life, unaware of what happened to him.

As for Thetis, I never ever felt her cosmo again after Poseidon´s Sanctuary destruction.

If we lost this war and the emperor of the seven seas will not come back before 250 years ...

Then why did Poseidon brought us back to life ?