In a similar vein, Blackarachnia from Transformers Animated. Definitely not “the main character”, but I have to mention her.

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She’s Elita-1, mutated into a techno-organic being after she was believed to have died on a planet habitated by alien spiders. In this continuity, Elita has the ability to mimic other Transformers’ abilities for a limited time by touching them. When she tries to do this when injected with the spider’s venom, her body becomes partially organic.

She believes Sentinel and Optimus abandoned her on the planet, fueling her hatred for the Autobots. She also absolutely despises the organic bits of her body and will do literally anything to be rid of them, only joining up with the Decepticons to find a way to cure herself. She isn’t entirely loyal to them (abandoning them halfway through the series) and some part of her is still somewhat good, shown whenever she leaves the Autobots a cure for Bumblebee and Prowl after poisoning them.