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human
[Transformers] Are Decepticons inherently evil? Or are they just led astray be Megatron?

I've always wondered, Decepticons seem to be, as a rule, evil! Are there any of them with any good in their matrices?
gpt
In the old G1 cartoon, it's pretty much the good vs evil thing, as all they were trying to do was sell toys, with an exception here or there.   
In the just recently ended IDW comics universe, the Decepticons started out as a force for change.  Megatron was originally a peaceful protester who didn't believe that a person's alt-form should dictate their life, function, career, etc.  So if a person was born/built with the alt-form of a big drill, the only thing they'd be able to do with their life is be a driller, no matter their inner desires.   Megatron wanted to change that, but fighting the bureaucracy led to escalation, death and eventually war.     
A lot of the original Decepticons joined because they felt the same way as Megatron, or they were outcasts.  Eventually seedier individuals would join the ranks because they saw an opportunity to make things better for themselves.    
After millions of years of all out war, the Decepticons went from a group of freedom fighter outcasts looking to change the world for the better, to an army of killers wanting to bend the galaxy's will to their own.   
You could say Megatron himself was led astray by Megatron.   
If you're a Transformers fan and a comics fan you should definitely check out the IDW books.  There is a lot of top notch story telling and character development there.