So I've been reading the Dragon Ball manga chronologically for the first time ever. I've just finished where Piccolo killed Raditz and Goku with the Makankosappo/Light of Death as VIZ translates it (love that name). While Gohan befriending Piccolo was definitely THE thing that brought Piccolo to the Light, I believe it was slowly in the works during the 5 years between the 23rd Budokai and the Arrival of Raditz. I think his redemption path truly began when Goku spared his life at the end of the 23rd Budokai. And then it took another turn.
There's a lot to consider. Some will argue that Piccolo Jr. was not as evil as King Piccolo from the beginning. I call bogus on that because in the 23rd he was clearly willing to vaporize everyone within the vicinity and was not bluffing. As someone who believes based on all evidence that Piccolo Jr. and King Piccolo are one-in-the-same, I think key factors and circumstances, as well as who Goku is at both respective times. Against King Piccolo, Goku was not fighting due to a love of fighting, but was seeking vengeance for the deaths of Krillin and Roshi. The Goku of the 23rd is a new man in a lot of ways, having trained his mind and body for 3 years with Kami. At the same time, he's the same pure Goku who wants to test his limits against stronger opponents. Defeating Piccolo Jr. in the 23rd just happened to coincide with Goku's ultimate goal to finally win the Tournament. When this became apparent to Piccolo Jr. upon Goku's victory, I think it humbled him, unbeknownst to him at the time. Don't get me wrong, Piccolo was still evil and still hated Goku, but he was changed. I think a part of Piccolo was perplexed at how different Goku's reasons for fighting and getting stronger were from his. The mere fact of Goku sparing his life made him see, albeit begrudgingly, that Goku viewed him moreso as a martial arts competitor/rival than an imminent threat.
The five year gap between Piccolo's second defeat and the arrival of Raditz is a particularly interesting portion for me. Since the world was in peace, it seems like Piccolo and Goku led almost a "Cold War"-esque co-existence. In other words, Piccolo did not attempt world conquest during this time because he knew Goku was stronger, and he knew Goku would also still be training and would thwart him again. The King Piccolo of old did not have such a rival to keep him in check, hence his reign of terror. And while compassion had not yet entered Piccolo's heart, I do think he had begun to have doubts about his true purpose. And he had developed a grudging respect for Goku. Piccolo asking Goku to team up with him against Raditz was a signifcant moment. While yes, Piccolo wanted Raditz out of the way so that he would pursue world domination without trouble, him asking Goku to team up with him was him acknowledging his respect for Goku as a martial artist.
The next turning point for Piccolo was Goku's death from the Light of Death along with Raditz. Piccolo at the time would never admit it, but I believe this was where he truly saw who Goku was, and thus began to respect him as a person. Plus, his purpose of getting revenge on Son Goku had been fulfilled. So what was next? Of course, Piccolo took on Son Gohan to train him. I tried to pretend that this was my first time seeing this story unfold (I, like so many North American DB fans, knew Piccolo has a hero first, villain second). Obviously Piccolo is wanting to bring Gohan's latent potential to aid in the coming fight against the Saiyans, but what is his hidden, more sinister motive? Toriyama still draws Piccolo quite sinisterly at this point, and Kami voices that Piccolo, knowing his death is imminent, plans to use Gohan to carry out his Demon King legacy. And despite all the stupid memes about Piccolo being Gohan's true father, Piccolo was cold, cruel, and downright abusive to Gohan. It was not "tough love." In a way, I think Piccolo was fighting his changing soul, trying to keep his cruel, vicious streak alive through having Gohan, son of his archnemesis, suffer and be molded into another Demon King. Yet, after Goku's death, I don't believe the idea of World Conquest appealed to him as much. He was fighting the respect he developed for Goku after his sacrifice (the reason I insist that Piccolo respected Goku at this point is that he voiced respect for Chiaotzu's sacrifice against Nappa). But as we all know, Gohan was the flaw in the plan. Gohan, and the fact that he learned to talk to Piccolo not as a monster to be feared, but as a master, even a friend, well...the rest is history.
Please let me know your thoughts, and (polite) disagreements are welcome. Piccolo and Gohan are my favorite characters (Krillin is runner-up) so I gave this a lot of thought lol.
