Obviously it’s poison based, I’m wondering what monsters can help additionally.
All are ultra-evolved apart from Tiamad and my end monster who is 93% there, & is only really there because it’s all I can fit with my current cost level.
I’m also wondering if I could have a better order?
I have 2 auto-poisons, and 4 massacres.
I can post more pics if required 
Not very good at providing ideas, but your team has very little support and too much offense, and would get torn apart by a well structured team.
I tend to use my stun-entrances as my support, (Thor and Cyber) & poison gas from various monsters to counter sleep teams.
It’s been working good so far, both recent Dev challenges down first try & floor rank <100 on the tower battles.
What support do you suggest? I have a couple tanks I could train up, but where would I use them in my team?
You should post in the Rate/Build My Team post so that ic3b0rn can help you with it
I would suggest at least a haste user to help out your poison massacre people. 250 TU is quite the pill to swallow especially when it most often just takes about half of the life of the other team. Aslo maybe a healer/give turn mon that you can get from the holy challenge. That way you can heal and just use give turn to splash huge damage. If you’re dedicated to an all out massacre team like yours it is better to be quick and agile rather than just bulky.