Which of the main 3 had the most character growth?

[Captain Cadaver]

As per @[mention]SSJ2[/mention]'s challenge.

Yugi, Seto and Jonouchi/Joey are treat as the main 3 characters in a way, particularly in the anime such as the Dartz filler or their legacy in GX. With that said, which of the bunch would you say developed and grew as a character the most?

I'd say it'd definitely be Jonouchi, with him growing from being inept at Duel Monsters to becoming a competent and independent duelist. Yugi had several times when he wished to grow, but was never given a chance to shine on his own rather than relying on Atem's help until right at the end of the series and Kaiba became quite static in his actions ever since the end of Duelist Kingdom, despite being the most dynamic of the main cast.

 

[Papasmurf]

Yugi had the best potential for development but him still continuing to rely on Atem for all his duels until Memory World (barring rare exceptions like vs. Pegasus and Brainwashed Jonouchi) made his development at the finale feel rushed and rather unearned, unless Atem' sharing his brain works like Exp. Share from Pokemon

Still, if you factor in how meek and weak-willed he was in the pre-DK portions of the manga, he grew significantly as a person by the end of the series so there's that I suppose.

Kaiba's character development is honestly more of a character rewrite due to how he was almost as unhinged as the likes of Yami Bakura and Marik back in Death-T, although it seems he did to an extent move on from his desire to be the absolute best with all three Egyptian Gods after losing to Yugi in Battle City. But we know how that worked out, because Takahashi had writer's block and decided to use the same plot structure as Pyramid of Light for DsOD

Jonouchi's development was OK, although him nearly being one turn killed by Yami Bakura in the Memory World and doing absolutely nothing of worth in DsoD was rather... souring.

 

[Pyro]

It would have to be Joey. He started out as a bully (at least in flashbacks) and turned into a very generous and caring person. He also matured the most as far as dueling skill went, from not knowing even the basics of the game to being one of the best in the world—third best according to Pegasus in early GX, though that's obviously anime-exclusive.

Yugi lost his timidness and became a confident individual, but it wasn't to the extent of Joey's development.