The next morning Soren left the inn he was staying at and went to the place that the 3 boys normally show up at. When he got there he could see a sleeping Luffy with a set of weighted clothes laid over his chest, looking at the scene Soren thought Luffy had gotten stuck under the clothes. Soren disregarded Luffy and let him sleep, he walked up to a big tree that stood a couple hundred meters behind Luffy and started his own training.
[Let's start off with some reps]: soren
Soren put on his weighted clothes and felt that he still felt a bit weightless so he started adding gravity magic onto himself, once he got to around 40x Gravity Soren began to start his training. After 4 hours of intense reps Soren was stopped by a voice.
[Hey Mister… Can you help me out?]: ???
Soren looked over to the voice and saw Luffy now awake looking at him with the weighted clothes still trapping him. Soren gave a slight chuckle before thinking of a way to train Luffy before the others arrive, then it hit him.
[Luffy… You must remove the clothes by yourself, if you can't do it, I will never let you become a pirate]: soren
[Whaaa!... HNNNNGGG!]: luffy
Luffy started to struggle to remove the weighted clothes that only weigh a measly 100kg, but when Soren thought further on it, he realized that Luffy was just an 8 year old boy who has no previous training in heavy lifting.
'This should be a good training for him': soren
Soren went back to his training and increasing his gravity to 45x gravity, starting over from square one he started with push-ups. After around 3 hours of consent reps with only a 10 minute break every hour Soren started to adapt to the gravity he was under quite nicely.
[HNNNGGGH!... Get off me!]: luffy
[Are you still having trouble getting these clothes off of you?]: soren
Soren started to walk over to Luffy to watch him struggle up close, when he got up to his position where Soren was standing with Luffy at his feet he spoke to taunt Luffy.
[What if you were in this same position when you entered the Grand Line and someone was over you, just like me. Then they take one of your friends and say "I will kill your friend if you can't move that weight off of yourself" What would you do?]: soren
Luffy heard Soren's words and his eyes widened, Luffy pushed with all his might and managed to lift the clothes just a bit.
[Come on! Or I will will kill both Ace and Sabo]: soren
When Luffy heard Soren's words he pushed the clothes with all his might, after another slight budge he yelled.
[GET OFF ME!]: luffy
Unconsciously Luffy started projecting King's Haki, Soren watched as a few birds that were flying over head dropped from the sky unconscious, and the clothes that entrapped Luffy were thrown to the side, but not by far.
[Hehe, good boy… Your training truly starts now]: soren
Soren watched a passed out Luffy as he thought those words, he then picked up the clothes that were right next to Luffy's body and realized something off.
[Hmm, These clothes… Fuck!... I'm surprised Luffy could even lift this in a rage]: soren
The clothes that Soren picked up were a set that he originally bought for himself but only noticed now due to the difference in weight with the ones he put on himself.
[These things weigh easily 600kg, this is 6 times as much weight as he should have gotten… Sorry Luffy]: soren
Soren took off his weighted clothes and up on the ones that were given to Luffy by accident and laid the ones he was wearing down next to Luffy.
[Oh yeah, I feel the difference now… Well, back to training]: soren
As Soren started his reps again with an increase up to 50x gravity a few hours passed and then 2 voices rang in Soren's ear.
[They're here]: soren
Soren got up from the rep he was doing and waited for the 2 boys to greet him, but when they saw Soren they asked.
[What are you doing here?]: ace and sabo
Soren was stunned, he didn't see their weighted clothes anywhere.
[Where are your training clothes?]: soren
The two looked at each other and then started laughing, Soren was this and tick marks started to appear on his forehead.
[Go home and get your Training clothes… NOW!]: soren
[Who do you think your talking to Mister, all I see is an old man trying to hang out with a bunch of kids]: ace
Soren felt hurt, he truly was an old man who was mentaly 40 but physically only 18, Soren then spoke up.
[Fine… Leave! I will be training only Luffy, you guys are not part of the deal with Shanks and myself]: soren
Soren told the 2 boys to leave but they didn't move an inch but instead started to scold Soren.
[This is our base, you are the one that needs to leave… And don't be trying to take Luffy, we are not letting our brother go with some pedo]: sabo
Soren then snapped as he focused his gravity magic and forced Ace and Sabo to be under 2x Gravity, they both fell from their feet instantly.
[He has a power like Luffy]: ace
Soren then spoke to both of them with a cold tone.
[You may leave, or you can stay and train with Luffy, these are your only choices and there is no middle]: soren
The 2 boys started to shake a bit before nodding their heads and running off. Soon Luffy woke up and eagerly looked at Soren waiting for his praise about how he lifted the clothes, but sadly it never came, instead, Soren said.
[Let's start training… I got you some lighter clothes, you should be able to put them on]: soren
Luffy looked next to him and saw the clothes, he tried to pick up the shirt and struggled a bit but managed to hold it in his hands.
[Mister… It's smells]: luffy
Soren was a little stunned at Luffy's comment and remembered that he trained in it.
[Just put it on, worry about the smell later]: soren
Luffy tried to put the shirt on struggling for a bit but managed to get it on, and then Soren spoke.
[Perfect timing… Now, Luffy you and your 2 brothers will start training.]: soren
[Brothers? Where?]: luffy
Luffy looked around but saw nothing until he heard some people walking towards them with struggle as they wore the weighted clothes as well.
[There… Now, the first thing you will do is walk around with the clothes, get use to them on your body]: soren
Soren explained to Luffy and when Ace and Sabo arrived explained again.