As we know, some characters significantly change throughout the story- may it be due to an incident or because they want to change. Here, I will present the top 5 characters of SoT and GoH that changed the most. I again mixed them both, so don't be confused.

#5 Taji Nakamura

Well, it might be surprising, but Taji did change throughout the story. His change however isn't happening on-screen, so it's actually hard to notice. But he did make a significant change in the story.
Taji used to be a character that used to quickly burst out in tears if something happened- when he was reminded of his suicide attempt, when he was saved from Kalani's control or when he found out about Laslow's death in US-W100, to name a few of them. He appeared to be desperate and hopeless, shy, blushing quickly and pretty done with his entire life. Now, a part of his change, we can witness on screen- after he battled Laslow, he took off his neckerchief and glasses, things that have actually marked him pretty much. He began having hope for his life again after the Eclipse War ended and he wasn't torn away. He no longer wished to die. But the greatest part of his change happens within the 20 year gap between SoT and GoH. Taji cuts his hair as he returns to Johto and attends university there. He grew much more confident and his shyness has gone away completely. Also, he has grown much stronger, not crying anymore if something bad happens (like when Laslow got shot- he didn't cry, he just felt sick). He left his previous life as a hacker behind (or at least tried so- he cannot really get rid of that completely) and even became friends with an Alolan Sandslash to overcome his Pokémonphobia which is common to occur for Fallers. This change actually is for the better and underlines how strong of a character Taji has become over the course of time. 

#2 Jacky Heavens

Jacky's change actually pretty much happens on-screen. She used to be the calmer, stronger and more reasonable one of the main characters of SoT- someone who could take on dozens of angry nuns and monks and keep her composure when something bad was happening. She was the one of the two mostly taking over the role as the planmaker (the Rebel Arc is a prove for that, just like Monastery Arc is). However, we see her entering the background more and more since Alola Arc. She started becoming insecure and self-doubting... We can clearly see that in League Arc for the first time where she had a "mental breakdown" after her nerve-wrecking battle with Chris Edwards which she was only capable to win after he practically surrendered the fight. But in Alola Arc and everything following, you can clearly see how much she has actually changed. Laslow took over the role she had before- the role of mastermind, and literally everyone else of the cast has become significantly stronger than her, even if they used to lose to her every time. She utters her self-doubts on a frequent basis, loses hope very quickly, even says that she is capable of absolutely nothing and belongs into a mental hospital. It also turns out that every one else of the four main heroes, Mari, Jayden and Laslow, appear much more frequent in GoH, while Jacky has just a tiny role here and there. This is definitely a change for the worse as it appears Jacky is just simply too weak to take on the world. It's actually quite sad tho.

#3 Ayuuki Hirano

Remember the girl always hiding under the table or behind Taen's back? The girl everyone uses to forget, but appears outta nowhere? The girl that is always stuttering and runs away most of the time? Ayuuki's character is quite a... unique one. But it is actually surprising that she is changing throughout the story. She does actually become more daring- visible in when she dared to enter the guild's pool and show herself in a bikini or when she dared to touch Taen's Flygon which actually is a dragon and has a dragon's wild and sometimes even aggressive nature (even tho Taen's Flygon is quite the tame one most of the time). There also is a time when Ayuuki quits the hiding and stuttering (which actually surprised the entire guild). Seeing her change actually was something I waited for.

#2 Akira Heavens

Another Heavens on this list, eh? Akira started off as a complete asshole, using Yukine as his stepping stone and punching bag, hating his foster father Laslow for... actually a really unjust and not even correct reason and even insulting and degrading everyone around him (Yukine especially because it's so easy to do with him). Might be surprising, but Akira does change his behavior towards the other guild members and most importantly, Yukine, at a later time. He actually starts being nice (most of the time) and tries to be a good friend to Yukine, something he failed to do all the time before. Also, he acts a lot more talkative and relaxed around Taen and starts getting along with everyone else in the guild. Also, after he knew the truth of his origin, Akira's thoughts and resentments towards his foster parents changed, as well. He started to appreciate and love them the way he should. Good he changed. Poor Yukine didn't deserve being treated like trash and Laslow and Taji didn't deserve to be hated just because they saved the world.

#1 Dino Adachi

Yes. Dino, who was the greatest asshole of all time, changed. He actually still is an ass, but at least he cares about his friends in his own distorted way. He can be understood much more since his story was revealed. However, the greatest past of his change happened in GoH. Actually, he got involved into the Ugoya case as he helped Taro Nishiki dealing with it. Also, he prevented Taen's imprisonment and even started to sort of be friends with the former Ugoya leader. We never saw him being committed to anyone like that before (except for Zain, whom he seemed to care about a lot, but who just disappeared without a trace at some point). His "friendly" behavior towards Taen is explained by the fact Dino can relate to him and sort of sees a part of himself mirroring within Taen. Also, Taen reminds him of Zain a bit, a precious friend he lost. In GoH, Dino actually is a loooot cooler than ever before- even preferred by the guild members above anyone else of his colleagues. And that means something.

Well, that's it for this section. Which characters do you think changed to most? Tell me your thoughts in the comment section!