Crash GrinSanity (A Crash Bandicoot Comic Dub)

Her Personality: 

In her first appearance in Crash Bandicoot Purple: Ripto's Rampage, Nina has an infantile personality and speaking pattern, referring to herself in the third person and calling Spyro a "purple puppy". This partly carried over to her next appearance in Twinsanity where she was more brooding and essentially mute. In subsequent games, however, these traits were removed in favor of a more intelligent, albeit sometimes childish and bratty personality. Canonically, Nina is known to be more ambitious and egotistical than her uncle; even Aku Aku believes that Nina is "a lot smarter than Cortex ever could be.", though it is unknown if she really is smarter as she needed Coco to build the robot in Crash of the Titans. Nina seems to be more "street smart" or has more (or less) common sense than her uncle. She is very spiteful and sadistic and has a Gothic look (though she seems to despise being referred to as such). She also has an antisocial demeanor, only working with people if she gets something out of it. The only feminine trait Nina really has is taking care of her 'nails'. She dislikes the Evil Public School as of Mind Over Mutant due to the perceived inferior value of her schoolmates (whom she describes as the "dregs of society") to those of Madame Amberly's private academy, where she saw herself as "the queen". She additionally hates Crash for being the reason for her stay at the Evil Public School, and also calls him "furball".

In Nitro-Fueled, her personality is taken from the Radical Entertainment era. She takes losing maturely in this incarnation, only expressing mild disappointment but also understanding that she needs to work harder to gain desired results.

Ref: https://www.youtube.com/watch?v=o5ncdhSGaIk

His Personality: 

Cortex embodies many of the classic traits of psychopathy, being short-tempered, reckless, having no apparent conscience (as cited by Doctor Nefarious Tropy in Crash Twinsanity), and frequently manipulating others to get what he wants.

Like many stereotypical villainous mad scientists, Cortex holds a grudge against other scientists for ridiculing his outlandish (yet workable) ideas, and was originally driven towards world domination by the desire to prove his colleagues wrong.[1] This no longer seems to be the case, as it is revealed in Crash Bandicoot: Warped that Cortex is working under the orders of Uka Uka (Aku Aku's evil twin), one of the only two individuals that Cortex fears (the other being Madame Amberly). Although Cortex talks big and acts confident in most of his appearances, he can be shown to become nervous (sometimes downright spineless) when put in the face of extreme and immediate danger (i.e. confronting Uka Uka, running out of ammo while fighting enemies, etc.).

Another notable personality trait is his stubbornness and inability to plan ahead or learn from his mistakes; he often relies on his minion Tiny Tiger to eliminate Crash by himself, despite the fact that Tiny is too incompetent to do so alone. This impulsive behavior is first witnessed in the opening cinematic of Crash Bandicoot, in which Cortex refuses to heed the warnings of his then-henchman Doctor Nitrus Brio and tries to make Crash the general of his army, despite numerous past failures.[2] Cortex can become quite irritated or agitated when things don't go his way, especially in Crash Tag Team Racing; while most other characters express mild annoyance when Crash fails to perform an errand for them, Cortex scolds and lashes out at him the minute he comes back empty-handed, calling him a "blithering imbecile", "cantankerous twerp" and saying "You're the worst mutation I've ever created!". Mutually supportive relationships with other characters is also evident in the crossover game Crash Bandicoot Purple: Ripto's Rampage, in which Doctor Cortex temporarily teams up with Spyro the Dragon villain Ripto to destroy both Crash and Spyro, only to start bickering with Ripto at one point.

Cortex's main transport - his airship, from Twinsanity.

Cortex is not above lying and deceiving others to fulfill his evil desires, most of which include gathering Crystals to power up his doomsday weapons. He frequently uses the gullible Crash Bandicoot to complete these deeds, most evident in Crash Bandicoot 2: Cortex Strikes Back and Crash Tag Team Racing, claiming in both games to use the weapons for "mass helping people" as he puts it. His egotistical tendencies also cause him to alter facts about his life, claiming himself to be the most popular student in his school, even though in reality he was an object of hatred among many students, one going as far as to toss a dagger in his direction.[3] Cortex's vain side becomes most obvious in Crash Tag Team Racing, in which he often calls himself such things as beautiful and pretty. He also owns an airship which he uses from time to time, a possible reference to his inflated ego.

For most of the time, Cortex doesn't care for the lives and feelings of others, caring only for himself and what he wants. While this seems to be the case in most games, the one moment in which Cortex actually shows concern for someone else is in Crash Twinsanity, in which at one point his niece, Nina Cortex, is kidnapped by an evil version of Crash. It is at this point clear that Nina is the only living thing that Cortex cares about as well as being one of his only redeeming qualities, with the latter going as far as thoughtlessly putting himself in danger of being mauled by the ferocious Evil Crash during the level "Bandicoot Pursuit". Besides this instance, Cortex is largely unempathetic, seeing others only as tools for his quest in world domination (although presumably he likes N. Gin, Tiny and Dingodile really, as he puts up with them despite their past failings). It is unknown whether Cortex feels any regret for replacing Nina's hands with metallic death-traps, though this is unlikely, given Cortex's psychopathic tendencies.

Ref: https://www.youtube.com/watch?v=nO93X4eNdlQ