Naughty Dog Era
Crash Bandicoot 3: Warped
Doctor Nefarious Tropy is introduced by Uka Uka in Crash Bandicoot: Warped as the creator of the Time Twister Machine, a device that will aid Dr. Cortex in his quest to gather the crystals in their original places in time. He later acts as the third boss of the game, battling Crash with his gigantic tuning fork. After defeating him, he flees to the space/time vortex, and Crash earns the Death Tornado Spin. After defeating Cortex while in possession of all the crystals and gems, the ending will occur where is possible to see the two fighting over Uka Uka and from time to time there will be a stretching noise.
His boss battle style includes a wave of what appears to be electricity moving horizontally and vertically. Then, he switches up the platforms, which form a path to him. N. Tropy kneels down to rest and he is now exposed. When he is hit he uses his time warp/teleportation ability to warp other side of the room. If Crash is next to N. Tropy while he is still attacking or not kneeling down, N. Tropy will smash Crash with his tuning fork, vaporizing Crash across time and space.
Crash Team Racing
N. Tropy makes a return in Crash Team Racing, appearing as an unlockable character. To unlock him, the player must beat all records in the time trial mode or use a cheat code. Tropy drives a sky-blue kart that. Like Tiny, Dingodile and Papu Papu, N. Tropy has high speed and average acceleration, but bad turning.
The epilogue of CTR states that he began tinkering with his time machine again and he was last seen entering a time portal.
Traveller's Tales Era
Crash Bandicoot: The Wrath of Cortex
N. Tropy has a minor appearance in Crash Bandicoot: The Wrath of Cortex, in which he is an attendee of Uka Uka's convention and an occasional enemy in the game, attempting to hinder Crash's progress by shooting at him with his tuning fork and racing against him in a car. He only has one line in the whole game.
He also appears in the level Eskimo Roll near the end shooting balls of light at Crash. Just like Dingodile and Tiny, he can't be defeated in this level.
In Crash Twinsanity, N. Tropy appears yet again. He is first seen after the Rusty Walrus chase in High Seas Hi-Jinks, with Cortex's old colleague, Doctor Nitrus Brio, who were seeking the whereabouts of the Evil Twins' treasure. After not getting any information from Crash they decide to "wring it out of him". Right after that, N. Tropy orders N. Brio to transform. After a boss battle, the now frog-like Brio springs into the air and hits the iceberg's edge, sending Crash flying to Cortex's Lab. N. Tropy reappears in the level, Ant Agony, along with Nitrus Brio and N. Gin, to steal the Evil Twins' treasure but was burned by Spyro the Dragon.
Crash Bandicoot 2: N-Tranced
N. Tropy is the main antagonist of Crash Bandicoot 2: N-Tranced, in which he teams up with his inter-dimensional crony, N. Trance, kidnaps Crunch, Coco and Fake Crash, and hypnotizes them into working for him. He is later defeated by Crash and is forced to take a group picture with the Bandicoots, much to his anger.
Crash Nitro Kart
N. Tropy is an unlockable character in Crash Nitro Kart, where he races under Team Cortex with Cortex, N. Gin, and Tiny Tiger. His face is shaped like an hourglass here. To unlock him, the player must defeat all of his ghosts in Time Trial mode.
Nefarious Tropy is, needless to say, a nefarious and smug character, as opposed to the childish outspoken temperament of Doctor Cortex, with a smooth British accent to match. He proves highly intelligent, his technological breakthroughs arguably the most advanced of all of Uka's scientists (having built a time travel device), tied with Doctor Nitrus Brio (having built a evolution accelerator device) and Cortex himself (having achieved dimensional travel). However he tends to get frustrated when he repeatedly misses his target, and as a result, tires easily. This usually works to Crash's advantage and results in Tropy's many defeats at the hands of the bandicoot. Like Cortex, he is also highly pompous and foul tempered, venting his frustrations at his associates or blaming them for his errors, something N. Trance was perfectly willing to call him out on.
Unlike most allies of Uka Uka, N. Tropy does not seem to be subordinate to Cortex, more of an equal and occasionally a rival for role as Uka Uka's right hand man. This can lead to conflicts between the two prideful doctors, it is Tropy that exposes Cortex's secret weapon in The Wrath Of Cortex in suspicion he is holding out on ideas, while in Twinsanity the two openly oppose each other for the Evil Twins' treasure, with Cortex ultimately mocking Tropy's comeuppance. Even as infants they both fight for usage of Uka Uka with equal footing in Warped. He seems to have an affinity for time related puns, rarely letting a sentence go by without one. He also shows glaring traits of OCD (obsessive-compulsive disorder).
Role in the Series