I could write multiple paragraphs on why Venoxia doesn’t work on a troop currently, but what it basically boils down to is the risk/reward ratio for the spell is way off. Taking the non-RNG components of the spell, you get an attack buff when the troop would die too quickly up front to make use of it, and true damage minor enough as to actually be overall detrimental in some cases. The biggest “reward” you get is self feeding and getting some blue. The biggest risk you take is feeding a ton of both blue and green to your opponent. It doesn’t help that Venoxia has to compete with Kraken, who is a “safer” spawner overall with much bigger RNG rewards.
First and foremost, Venoxia’s role needs to be decided, and it needs to have properties that let it fit into that role. Is it a growing threat first or second slot? Status synergy? AoE true damage? Mana feeder? Self looper? Which of these is most important to its identity? If it does all of these things well, it is blatantly overpowered, but right now, it really does none of them well.
Thematically, we should start with the poison and build from that. This is what the kingdom is supposed to be most known for. This is one of very few dual spawning self-loopers and I also would consider that part of its identity, however, this alone is going to cap its effectiveness. We can at least make it consistently do something, though. The attack gain seems the least relevant thematically (and pragmatically), but also has two of the three traits supporting it and is the biggest component of the spell. Having full scaling AoE true damage and arcane and self looping and feeding troops that can feed it would obviously be a mistake, so I’d strike that right away - it would need to be half scaling at most, maybe even scatter damage, depending on the focus.
Given all that, I’d like to see one of the following:
Support oriented true damage:
Noxious Gas: 15 Green/Purple. Create 8 green and 8 blue gems, boosted by poisoned enemies (1:1). Deal [magic + 4] true damage randomly split amongst enemies and reduce their attack by 4.
Traits: Indigestible, Huge, Miasma.
True Damage oriented support:
Noxious Gas: 14 Green/Purple. Create 9 green and 9 blue gems. Deal [magic / 2 + 1] True Damage to all enemies, and 5 more if they are poisoned.
Traits: Arcane, Huge, Miasma
Venoxia type from Dragon to Naga/Dragon for even better synergy with the mythic.
Values are intentionally left low here because of the self looping potential. We can’t have Venoxia team wiping in three casts when it can trivially chain three casts in a row by itself, even if each cast is “risky”.