Donnie is the third youngest of his four brothers. His 'twin' brother is Leo, Raph is the oldest and Mikey is the youngest. Donnie has autism, and his hyperfixations include: science and technology, Jupiter Jim and pizza. He brags about how amazing he is, how he's the best, but actually, under all that, he's just an insecure guy... He's emotionless, on the surface. His autism makes it hard for him to feel a lot of empathy. He's a narcissist (a bit) and he's very sarcastic. Donnie is non-binary.