Gentle Giantesses

By the way this is a kind of base idea, if you want to use it for the crossover, feel free to.

The story (Blake's Universe) would happen after the events of Shrunk wth your Girlfriend/GTS (in the GTS storyline).

[Previous, short version of what my story was supposed to be in the GTS line]
Corrupt agents tried to use a top secret substance to make super soldiers on average teenagers, and unfortunely, those were Blake and Joana, who were on a date. Joana grew to enormous proportions (limit 80 meters). Joana had also sharpened senses and maybe got slightly stronger. The agents after discovering the amazing growth, tried to use her as a massive destruction weapon but she refused, and they weren't able to control her. Then they tried to kidnap Blake and threaten him to have her obeying their orders. But before they got to talk to Joana, she went furious in a rampage to find Blake, destroying almost half of the city in the process, Meanwhile, Rick and Blake's friends were in a laboratory developing an antidote for the growth, since Joana was destoying everything until they gave Blake up. A little before being accidentaly crushed by her, they escaped and went to get Blake back. They needed Joana as a distraction, so they didn't give her the antidote yet. They freed Blake and just in the moment before Joana crushed the building where they were, they got out, and showing her that Blake was safe, she agreed to take the antidote. Then, when shrank to normal, she fell in Blake's arms, exhausted...

In middle of the story Blaze appeared challenging Blake, winning the first match but losing at the second, at the end, because Blake got stronger, and he would want a revenge...

[A few months later]

Blaze observed Blake's life from afar, and knowing what happened when Joana grew, he thought he should use a girl that way, to make he unstoppable but obeying him. And realized that Joana and Cinthya were the worst enemies, almost as he and Blake were.

Then he sneaks and steals some of the growth potion, then appears suddenly with Cinthya alone and after making her to tell him how much she hated Joana and how much she wanted Blake, he offered her the deal...

Meanwhile, sue to what had happened and some further Blaze's brief appeareances, Blake decided to train Joana about fighting, she already knew a few things Karina once taught her, but it wasn't much, so she began to learn to fight with Blake as her teacher.

In a moment (here could be the cross over involve) Cinthya takes the substance and grows, beginning to destroy the city. Blake appeared and tried to stop her, but Blaze interferred, then Joana used the substance also, so there would be at least a double nemesis fight, Blake vs Blaze and the GTS catfight...

(In those events can happen many other things related to other universes but I don't know). A possibility was that Blaze joined to villains or evil characters from the other stories.

Brief Blaze description:
Species: He was supposed to be human but now nobody's sure.
Height: 1.82 (slightly shorter than Blake)
Hair: Long and White, it covers his eyes
Skin: Very pale
Eyes: Red (only a few times seen)

Blaze is an unknown being with overwhelming strenght, he fought Blake, seeing the potential in him and then, he told him that his environment was way too soft for him. He seems to have trained for long time, and he must be older than 16, that is his age appeareance. Furious Blake was almost at his level. Even Blake, strenghtened after the experiment where Joana went GTS, was barely able to win. Blaze seemed to hold back and has never shown his true strenght, until fought furious Blake. Despite all, he's still evil and only looks for a "good fight". His lifespan is also unknown. (In the future he'd appear to challenge James jr, and still seemed 16)

I hope this helps you somehow.