|Title||Joseph Albert Nefario (full name), Dr. Nefario|
|Film||Despicable Me (2010), Despicable Me 2 (2013), Minions (2015)|
|Hair Color||Gray (formerly Brown)|
|Friends||Felonius Gru, Marlena Gru, Margo Gru, Edith Gru, Agnes Gru, Lucy Wilde, The Minions, Kyle (pet)|
|Enemies||Vector, El Macho|
Dr. Nefario dresses like a stereotypical mad scientist. He is generally elderly, mildly overweight, and is apparently hard of hearing, which frequently gives him trouble with initial consonants. He is always seen with his labcoat, gloves, and trademark goggles, and he wears either pants or pajama bottoms with a plaid pattern. His hair, what little there is of it, is longish and faintly unruly.
In Minions, it is seen that he wore glasses in his youth, a yellow shirt underneath his labcoat, and black trousers.
Dr. Nefario is Gru's closest and most loyal friend who always comes to his rescue. He has a very high respect for Gru and even believes he is the greatest villain in the world, but he often doubts his abilities and motives. He is also quite eccentric with rather bad hearing due to his age, but although he seemed a little odd at times, he did not seem to be going senile.
Dr. Nefario doesn't like to be unproductive, as he has constantly been seen working on projects to aid in Gru's crimes, and even decides to work for someone else after Gru renounces his former life of villainy.
His accent suggests a British family lineage. Nefario seems to enjoy disco dancing and is even briefly shown doing so alongside Marlena Gru, and in the Boogie Robot scene.