I've been debating this in my head for a good 20 minutes now. I mean, yeah, he doesn't live in a tribe or anything like the others do but he fits the description. Only major difference being he uses chem weapons rather than physically fighting and that he lives in a (mostly) human civilization. Either this or he's an experiment of some kind that went horribly wrong...
he is a plague rat it is likely his species was mutated by the chemicals in Zhan
Since he's in Zaun, he's most likely an experiment like 
.
No, he's literally just a mutated rat.
They confirmed that only the champs that are listed on the vastaya page are actually vastaya.
Everyone else is something different https://universe.leagueoflegends.com/en_GB/race/vastaya/
No, he's just a big ol' ratty boy. All the pre-existing champs that were made into Vastayans were updated when Xayah and Rakan were released, so only Ahri, Nami, X&R, Rengar, and Wukong are Vastayans.
Unfortunately, he isn't. Twitch is just a heavily mutated rat.
Nah Twitch isn't a Vastaya.
To be a Vastaya, you have to be a descendant of the Vastayashai'rei, which, Twitch clearly isn't.
Iirc mutated Plague Rats like Twitch are a sorta-but-not-too-common occurrence in Zaun. Twitch is just the freakiest example of them.
Speaking of Vastayas in Zaun however, Warwick's whole creation is actually partly thanks to the Vastaya. In Singed's notes, he mentions that he based some of his work on 'Subject #1088 AKA Warwick' off of some research from his chemical attack during the Ionian invasion. It's also clearly stated that Warwick is actually more chimeric (just like the Vastaya) and not just a simple humanoid wolf (His ears are that of a bat, his tail is that of a fox and the rest is wolf of course).
I mean... Vastayans are people with few animal parts. Twitch is literally a giant, bipedal rat.
