[Guido]

This is confirmed true to what JShaggy had previously posted, as I witnessed it myself.

I speculated my suspicions about Roze since the tenth episode when taught Solty that humming song.

Spoiler:

But miraculously having survived the Blast Fall had unexpected side-effects on Rose (Rita). Her hair changed from reddish-brown to blonde, and I'm also remarking that in episode tenth she suffered a sort of bodily exhaustion as strange purple marks started to appear over her body.

Thus indicates that nothing is all well with Rose/Rita and might had caught a disease or congenital syndrome, product from Blast Fall, that will manifest itself on a later episode.

Roy's unexpected reunion serves to close this arc, and Solty Rei is moving towards the second arc which likely will answer all questions fans had formulated about Solty's origins.

Spoiler:

At the start of Solty Rei, I thought that Solty may had been either Roy's original daughter or being responsible for Rose/Rita dissappearance.

Since Roy & Rose/Rita had been reunited, the first scenario is now discarded and opens the door about future Solty scenarios.

What I believe was that Solty being responsible for triggering the Blast Fall twelve years prior.
She was designed as weapon of mass destruction by RUC, but they could not contain her massive powers.

Over the course of the years Solty was redesigned and turned into a humanoid Resemble able to mimic and reproduce the personality of a living human likely for RUC to tame her for their research and testing.

There is evidence that could sustain my theory.
- 1. Everytime in need , danger , or just being provoked, Solty powers up and her hands start to vibrate at ultrasonic speed unleashing unexpected bolts of power.

Well, I expect the next arc will display everything about who is Solty for real.