u/Hefty_Drink_5811

The virus and its infected would be able to adapt to any/all environmental conditions. It would infect any species, lifeforms, and living matter from Earth and beyond, not just humans.

It'd be completely incurable. It'll be more contagious than all known pathogens combined. It will enter bodies and infect anything organic through all possible pathways.

The infected will only become the evolved. No walkers, hunters, brawlers, juggernauts, hydras, flyers, goliaths, etc. Just the evolved. Although they'll be able to shapeshift into those things at will.

Not only that, but the evolved, after first being infected, will be like if James Heller first became an evolved and immediately consumed Alex Mercer, right before he wakes up from a morgue, and Pariah, right after being born, at the same time.

Each Evolved can develop all known powers and evolve to overcome all known weaknesses, with or without the need to consume.

Heller: Hmm. Looks like you're on top of the food chain again. For now.

Mercer viciously consumes Heller with his claws. He absorbs Heller's memories.

Heller: This is for your own good, baby. You'll understand at some point.

Amaya: I understand that I had a father once. A general and war hero named James. He and my mom would ride roller coasters with me whenever he could come home. I understand that both my parents are dead now.

Heller: Your mother is a part of me now. Forever. And I'm no longer bound by the concepts of life, death, division, and imperfection, Maya. Pariah moved me beyond those things. He did the same thing to Mercer. He just doesn't realize it yet. Soon, Pariah will do the same thing to all life on Earth.

Memory flashes end. Mercer unleashed a massive barrage of tendrils that allowed him to consume the entire virus and all of the infected, effectively ending the second outbreak of the Blacklight virus caused by Heller. Mercer finds Maya and Dana in a bank vault.

Dana: Alex! Thank God.

Mercer: Is everyone alright?

Amaya: Yeah. We're good. Is it over?

Mercer: Yes. For now.

The three look at the sunrise and all over New York from a rooftop. Alex began to walk away from Dana and Maya. Maya stopped him by grabbing his hand. Alex put his hand on Maya's shoulder, and they looked at the sunrise together.

Dana: What do we do now?

Zirin harbors all of Azula's negative traits but none of her redeeming qualities and lacks all of her sense of level-headedness, thus Zirin's unable to lightningbend.

Both Azula and Zirin use fear as a tool, but while Azula uses intimidation to establish dominance and order, Zirin uses fear to sow seeds of chaos.

Both Azula and Zirin could work for Ozai, but Azula is genuinely loyal to him and loves him. Zirin, however, would only follow him if he was too strong and clever to betray him, but she would 100% betray him if that wasn't the case.

Azula, in her own twisted way, truly cared for Mai and Ty Lee and felt genuinely hurt by their betrayal. Zirin wouldn't hesitate to throw anyone she works with under the bus.

Though her machinations are cruel, Zirin's informal approach to villainy makes her a broadly comedic character with a self-aware, irreverent style of humor (though her jokes are usually played for her own twisted amusement and at the expense of others).

However, this is partly surface level; Zirin is eternally bitter and imperious, with an uncontrollably fervid temper. At times, the smallest inconveniences can send Zirin over the edge, causing fiery fits and extreme damage to the area and people around her, depending on the situation. This quality makes her a feared figure among the fire warriors, some parts of all remaining nations, and even Azula at times; other times, she just finds her irritating and has the hardest time keeping Zirin under control.

If Zirin was animated in ATLA while it was still airing, I imagine her being voiced by Hayden Panettiere. I bet the fandom would even call her Ghostface Kirby.