This was one of the usages of the force-breaking technique he invented. His technique not only affected himself, but it also controlled and affected opponents' force, which could deflect and break enemy force. He was going easy on both of them. If he wanted, he could break all their bones by just reversing their Qi and force attacks.
After a while, looking at bruised and exhausted Goten and Trunks panting heavily, lying on the floor of the ship, sweating constantly.
"Well, it seems you aren't the strongest. So, in the future, you must act cautiously and not cause trouble. Do you understand?" Eero reminded kindly, looking toward them with closed eyes.
Both Trunks and Goten shivered, sat up, and nodded constantly. "We understand," wiping their sweat.
'Big brother Eero is scary,' Goten thought in horror. No matter how much they tried, they couldn't land a blow on Eero. Instead, no matter how much they controlled their Qi and force, they still couldn't help but abuse each other.
Eero stood up and walked outside the room. Instantly, he paused, looking at the smile on Vegeta's face. "I didn't expect you would reach such a height in just a few years. I challenge you to a fight. I want to see the limit of a mortal human."
Eero raised his eyebrows, then relaxed, replying calmly, "I accept your challenge, but you have to wait for a day or two. Also, I will not go easy on you."
Vegeta laughed loudly, "Ha ha ha, I like your confidence," then walked away, leaving speechless Eero.
"Don't mind him, little Eero. He is always like that," Chi-Chi appeared and spoke displeasingly, then asked curiously, "Have you seen Goten and Trunks?"
Eero nodded and pointed at the room behind. "They are inside, that room, Auntie."
Chi-Chi nodded with a smile and walked inside. On the way, she spoke, clenching her fist, "Beat him up and show him what humans can do. I believe in you."
Eero nodded with a smile. Next second, afterimages appeared again in his mind, a youthful girl speaking in the same gesture and a similar sentence, "I believe in you, little brother Eero."
Eero's eyes widened. He felt a sting in his brain, his brow furrowed, rubbing his forehead. 'Who is this girl? What is my relationship with her? Why am I receiving these flashbacks?' He fell into contemplation.
Then his eyes widened, realized something, "Wait, it must be related to the incident that happened to me at the age of six on Earth. The doctor said I was paralyzed because of an accident, but I couldn't recall that incident all these years."
"I must find out. This girl must be my relative," Eero muttered firmly, released his fist, relaxed, and walked toward the sweet table.
While on the other side, on King Kai's planet, Goku trains by blasting a Kamehameha which makes a complete circle around the planet, catching his own Kamehameha and controlling it. King Kai gets angry with Goku for not warning him, mumbling to himself how that's another reason he doesn't want Goku to meet Beerus.
Goku hears this and asks King Kai who he is. Seeing as he has no other choice at this point, King Kai finally explains who Beerus is. He explains that he is a God of Destruction, and as such, his job is to destroy planets. Upon explaining everything to Goku, he tells him to hide.
Beerus arrives with Whis and greets the North Kai, who is terrified at his presence. King Kai tries to stay calm, warned by Beerus that he'll shrink his planet even more if not satisfied by the food. When asked how long it has been since they last saw each other, King Kai answers that it has been 327 years. Goku is discovered by Beerus hiding and is told to come out.
After Goku informally introduces himself, much to King Kai's dismay, Beerus glanced at Goku. "Do you know about the Super Saiyan God?"
Clueless to what Beerus was talking about, Goku started scratching his head, replying, "I know about Super Saiyan but don't know about Super Saiyan God."
Beerus then decides to travel to Earth to ask the other Saiyans if they know something. Before they left, Goku asks Beerus to a fight to test his power.
Goku transforms into a regular Super Saiyan and charges after Beerus, missing every punch in the process. He then ups his power, transforming into a Super Saiyan 2, but still misses every punch. At last, he is forced to ascend into his most powerful form, Super Saiyan 3, but still misses every punch and unleashes a Kamehameha that tears through the other side of King Kai's planet.
He continues to throw punch after punch, to no avail. After that, Goku is frozen as Beerus hovers over to him and flicks his forehead, sending him flying. Then Beerus appears behind him, grabs his shoulder, reverts him to his base form, and knocks him unconscious.
Beerus and Whis say their goodbyes to King Kai and leave. Looking at their disappearing backs, King Kai wipes the sweat and sighs in relief.
Next second, he recalls the last dialogue of Beerus, his face turning pale with fright. He hurriedly informs Vegeta telepathically and instructs him to make sure nobody angers the God of Destruction, or Earth and its inhabitants will perish.
King Kai then tends to Goku, who wakes up after momentarily being unconscious after the devastating blow from Beerus.
Goku is in major pain and is told by King Kai that he's lucky to have survived the fight against Lord Beerus. Goku says he needs to get up and save Earth, but is told to rest. After he is fully healed, Goku decides to sit around for a while and wait it out.
Before Beerus and Whis arrive on Earth, Vegeta is pondering how somebody as strong as Kakarot could be defeated in just two blows.
Next second, Vegeta's eyes widened, feeling a figure standing on the cruise ship beside him.
Beerus slightly touches Vegeta with the nail of his finger, and Vegeta nervously stumbles away from him. Vegeta tries to attack him, but Beerus' glare causes his body to paralyze and make him fall down.