Rhydon's character in a nutshell
Rhydon is a rude beefcake character controlled by Nidoqueen.
Origin
Pre-Unova
Rhydon originally came from the Kanto Safari Zone, taunting Pokemon ever since he was a little Rhyhorn. This habit intensified once he evolved into a Rhydon, harassing Pokemon of all sizes and even picking fights with some. One day, his rude personality and immense strength and carelessness caused him to (seemingly) kill Zangoose indirectly, by pushing her off of a diving board and into a pile or rocks while vacating at her home in some springs. This was the first of many acts to cause the majority of the Pokemon world inhabitats to hate his guts
Post-Unova
Rhydon has gained much more importance after the desctruction of the old world. One of the first things he did after discovering this new world was open up a gym, realizing the profit he can make, as well as teaching other Pokemon of his cynical ways. Outside of the Gym, he continues with his crude beefcake ways, and harasses anyone he comes across. This usually ends in him biting off more than he can chew, but many other times he has won some challenging fights with his sheer power... and the help of his recent RNG diceroll lover. This power is so great that it is capable of completely levelling a hospital or just straight out killing someone. However, it does not protect him from water, psychic energy or leech seeds, all of which have led to his demise countless times.
Personality
Rhydon is extremely rude, hostile, and egotistical. He seems to care for no one except for a select few Pokemon. He is also obsessed with becoming stronger, yet, strangely, refuses to evolve, probably so he can abuse his Eviolite. Despite this, he is already quite strong as is for an NFE Pokemon. He also seems to have an accent, more specifically one of a New Yorker, as he talks using -in' instead of ing, 'em instead of them, sometimes you's instead of you, and so on.