Unfortunately an out of control child is going to grow up as an out of control adult. What is a temper tantrum as a toddler is acceptable and normal, but most people grow out of that and learn emotional regulation. Unfortunately many abusive adults are impulsive and lack emotional regulation because they missed out on an important part of their development.
An adult toddler is a scary thing. Having lived with an abusive ex, I can tell you this for real. I did not find out until later that he had been in a remand home as a kid, for behavioural disorders. I never did find out what they were...
Some children CAN be manipulative. I agree with Smileless there. I have worked with children for most of my working life, so I have seen and heard a lot of upsetting things, attended Social Services meetings etc. Sometimes children lie about awful things, but I still think you should believe everything and then investigate it.