Although Joe Pearson created the original characters, he has always believed it was Charles Zembillas who gave their designs the life and flair we're so used to. Joe and Charles were very cooperative and had a great team dynamic, which allowed them to pass ideas to and fro and spruce up designs where needed. Charles came up with the finalized art style the characters used in the original games.
It's through Charles's own efforts that this knowledge and much of the original art was finally revealed to the public through his blog. As with Joe Pearson, his role was written off by Naughty Dog as simply providing a series of minor tweaks to something they had already established. To quote Charles himself:
How many people knew just how extensive our involvement in the creation of Crash was? In the very first article about Crash when it was released in September 1996 Jason was quoted as Joe and I coming in to tweak Naughty Dog's work. Our involvement was misrepresented and trivialized.
Charles accepted Jason Rubin's apologies and continued to work with Naughty Dog up to their next franchise, Jak & Daxter. Charles Zembillas was once again brought for the character design, and even though he got the ball running, designed Daxter and created over 600 pages of art for the game, he was miscredited one more time. In Charles's words:
(...) nobody held a gun to [Naughty Dog's] head and forced them to leave Universal or sell out to Sony in 2001. This is something they wanted to do. (...) The intent to sell to Sony was something these guys always had in mind I believe based upon my experiences with them. That's why they misrepresented important facts in the history of both Crash and J&D. They wanted to make it seem that their project development was coming from inside their studio when in truth it wasn't. They had to contract out the design and development of both of their intellectual properties.
Early Daxter design(...) ND was desperate at the start of Project Y which became J&D. They were under a great deal of pressure. They left Universal and were on their own dealing directly with Sony. They were going to be funded on their next project by Sony and Sony was waiting to see something. They had to have a powerful follow up to Crash. They were so desperate to get art going for a new project they sent their entire development team to my school to train in character design. I knew what was happening at the studio cuz Bob Rafei was my student at the time. I offered to help out with the project and he took my message to Jason and that's how J& D came to be.
I worked for an entire year on that project. All through the year 2000 for a full 12 months. It was the first game where I was making some decent bucks. I created 603 pages of material for J&D. I designed the project from scratch creating looks for characters that still influence video game design to this day.
It was in my contract to be given credit under "Character Design".
Why would Naughty Dog give me credit under "Additional Character Design"?
On a side-note, Bob Rafei was one of Naughty Dog's artists, hence Charles's remark. He continues:
When Daxter won Best Original Character in 2002 at the Game Developers Conference in San Jose, California, the press release that was sent out through Naughty Dog and authored by Bob Rafei acknowledged and thanked several people for their work on Daxter. You know how I was acknowledged? That's right. Tweaking or making adjustments to their designs which was a bald face lie. Daxter was completely original. I looked at nothing. I was directed to look at nothing from the start of the project so it could be original and unique. I'm even posting the development drawings for everyone to see on this blog of how I developed the look of the character. How could I have possibly done Daxter by making adjustments on what Naughty Dog was doing?
(...) I created so much art for Project Y / Jak and Daxter that it saved the production and saved Naughty Dog and gave Sony the confidence to fund ND and eventually they bought the company.
They broke their contract by not giving me appropriate credit on J&D and they lied about my work on Daxter. That's how I was thanked.
Both Charles and Joe did eventually create more art for the series, as they returned to reprise their roles in Crash Nitro Kart. Thankfully, the studio behind this game, Vicarious Visions, had a better policy than the Naughty Dog from the late nineties. Charles concludes his thoughts by saying that, despite all the low points he experienced, he's not holding any grudges and enjoyed working with the team on both franchises:
I had a great time on the games while they were happening and I do appreciate the chance to work with them when it came around back then. I'm happy to see how well they've done. What they achieved is special. Like I said there's no hard feelings. My biggest disappointment is the friendship I once had with them is gone.
Charles continues to draw Crash Bandicoot-related pictures to this day, remaining very fond of the character and wishing for the franchise's revival.