After a grueling year of trial and error Thorn was finally able to train with Whis again. The reason this took so long was down to Thorn being a bit arrogant and saying Whis isn't helping out with his training efforts. Whis taking offense to this forced Thorn into the current training regiment with Thorn saying afterwards "Next time...I'm listening to you..." Thorn was completely exhausted by this and for good reason, Whis had been using a bit more power and speed than usual as Thorn was having to amplify his power and speed just to keep up with Whis! It was then that Whis told Thorn he could could take a break and Thorn didn't argue as his body was exhausted as well as his energy was all but drained completely.
(1 hour later)
After taking a nap and eating a small meal from Earth that Whis had stored in his staff Thorn sought out his mentor however he instead found Vegeta who was currently training with Beerus. Lucky for Thorn they both didn't sense him watching and during Vegeta's it was clear that Beerus was teaching Vegeta something new something a bit more...arrogant. Thorn went to leave and find Whis however he sensed Vegeta's power skyrocket and after a few minutes all Thorn saw was a flash of purple light and then once it cleared he saw this:
Thorn's eyes widened as now Vegeta and Goku were ahead of him! Not only that but they both found something that wasn't Super Saiyan Blue like he was doing however that didn't discourage Thorn but rather it made him more focused than ever. He flew off with Vegeta noticing this and saying "Thought so...hope he got a good look at this power."
(Lakeside-Beerus's Planet)
After finding Whis and telling him he was ready Whis ordered Thorn to power up to his SSGSS3 form. Thorn nodded and this is what Whis saw:
It was then that Thorn was finally back to his SSGSS3 form and this didn't go unnoticed by Vegeta who arrived after feeling the whole planet shudder from the pressure and weight of Thorn's power. Vegeta looked over at Thorn and upon seeing his form Vegeta smirked like he usually did and said "Well now...I'm impressed Thorn! I imagine you feel fairly powerful in that form? How about we see how strong it really is?" Thorn didn't answer but he simply looked at Vegeta and observed Vegeta's power now that he was closer all while thinking (Hm...that's his new form huh? It feels like he's back to when we first met...that must be what Beerus mentioned to me about lack of emotion when it comes to killing.) Vegeta crossed his arms and stared down Thorn who was uncharacteristically quiet until finally Thorn moved at such a rate of speed that by the time Vegeta had turned to see where Thorn was he had already moved above Vegeta's head and was inverted to look down at Vegeta. It was then that Whis and Beerus who joined later both saw the two Saiyans staring each other down until finally Thorn said "Good luck with your training." Thorn then moved back to Whis and the two continued their training with Vegeta wondering what the hell just happened while Beerus was thinking to himself (Looks like Thorn managed to control that form more than before. If Vegeta isn't careful he'll lose to that Saiyan.) Beerus instructed Vegeta to continue his training and that was what Vegeta wanted to do but not before saying softly "His eyes...they were yellow. What does that mean?"
(2 months later)
After completely mastering the drain on his form Thorn had finally sighed and it wasn't a simple one. For Thorn that sigh was his way to finally saying he finally completed his objective and he needed a chance to rest. Whis then said stopping Thorn "I hate to do this but I have something I'd like to test. I'd like for you and Vegeta to fight using whatever you both have left. It'll give myself and Beerus an idea of what we need to focus on in your training." Thorn agreed to the idea and later on Vegeta agreed however both men were too low to go into their god forms. Both men met up then they squared off with Thorn rushing in a giving Vegeta a serious kick to the stomach that sent the prince flying however he caught himself then Vegeta vanished and appeared in front of Thorn only to deliver a roundhouse kick that Thorn blocked however because of the force Vegeta used the impact was enough to send Thorn flying towards the lake. Thorn recovered but to his surprise Vegeta was gone! It was then that Vegeta appeared above Thorn and kicked Thorn right in the face sending the Saiyan into the lake at a quick rate of speed. Thorn emerged from the water and went on the offensive with the two men doing this:
(Thorn is taking Goku's place with Vegeta taking Cell's place for context)
Thorn and Vegeta landed after their little spat then Vegeta said "I know you're low on energy and I know you'll try to be conservative but you know this...even you can't beat Super Vegeta!" Vegeta powered up to SSJ2 while Thorn simply smirked and said "Maybe so but you know this Vegeta...you can't do this!" Thorn powered up to SSJ3 and for Vegeta it was the second time he had seen the form but it was the first time he'd ever seen Thorn use it and Vegeta simply did this:
He was shocked that Thorn not only was in a form ahead of his own but Thorn made it look effortless and from Vegeta's perspective Thorn made SSJ3 look so comfortable like it was natural to him. It was then that Thorn did this to Vegeta:
(Context.)
After the little spat of attacks from both Saiyan warriors Thorn stared at Vegeta then he said "You're leaking energy Vegeta...even I can sense it and I'm hardly paying attention to it." Vegeta thinking Thorn was bluffing ignored him until a few minutes later when Vegeta was so low on energy that he couldn't even maintain Super Saiyan while Thorn was as collected and reserved as ever and still able to be a Super Saiyan 3! Thorn spit out a little bit of blood from an earlier attack then he said to Vegeta "What's wrong prince? Is someone angry at the fact they can't keep up with a low class dog?" This angered Vegeta even more and it made him to do this:
After taking that barrage of ki blasts and after hearing Vegeta say he beat Thorn it was only fitting that Thorn emerged from the smoke cloud and said to Vegeta "You were saying prince?" This made Vegeta stand there in such a state of shock that he never noticed that Thorn disappeared until finally he heard from above him "Get ready for the real deal!" Thorn then prepared a Kamehameha however he failed to notice that instead of the usual blue aura this time it was red like the Kaioken. Thorn then said "Sorry Vegeta but you can't beat me not at your current power level. This battle is over." Thorn then did this:
After taking a fair amount of power from Thorn's attack the mighty prince Vegeta had fallen to the ground defeated physically however his pride wouldn't let him quit so he simply stood up wanting more until finally Thorn said as he appeared behind Vegeta "Stay down. You can't fight in your condition." Thorn then chopped Vegeta's neck knocking him out cold. Whis and Beerus arrived with Thorn saying just before passing out "Looks like I won...ugh." It was then the mighty warrior passed out with Beerus catching him saying "Good work Thorn. You've proven yourself to be a worthy opponent." Whis looked at Beerus and thought to himself (Even after all that training Thorn still beat Vegeta without using Ultra Instinct or Ultra Ego.) He then looked at Thorn and continued that thought by adding (What makes this saiyan warrior so unique? No one should be able to fight off something like Vegeta used But yet he did and successfully pulled it off. You've earned that rest Thorn, sleep well mighty warrior.) It was then that Whis and Beerus left the two warriors to rest peacefully all while Beerus thought to himself (I'd better watch him carefully...if he could match and overpower Vegeta then it's only a matter of time before he does it to me!)