Sirius ended up learning the spell in 2 weeks due to the help of his 2 Shadow Clones and mastered some other spells Aldoron taught him.
Naruto watched the spectacle in joy as his father and son step past their differences and enjoyed themselves. He too joined in the fun and they remained like that for a couple more years.
After putting all of them to sleep, Sirius felt someone sneak up on him and moved from the spot he was and that saved his life. Just after he moved, a reaper cut the area into pieces.
"Show yourself or else I promise you the worst pain to death," said the man with a red reaper in hand.
He looks much like the stereotypical thug boss, clad in black clothes and a mask that leaves only his black eyes and the upper portion of his nose exposed. He bears his gang symbol on his chest and has a reaper in hand.
The Reaper has a decorated red sickle and a barbed circle-shaped weight, connected with a chain. Sirius can see the weapons long and short attack range as the thug can manipulate it with the chain.
"How did you find this and how many else did you come here with?" Asked the man in annoyance. Sirius revealed himself with his sword in hand. He is not going to take chances here. He tried performing his Sleeping Jutsu on him, but the man in front of him laughed at his efforts.
"Don't bother using that sleeping spell. It won't work on me."
"I have an air filter in my mask which nullified your mist," he further added. Sirius thought about it. That is a plausible explanation of how he didn't fall asleep like others.
"Let me make this clear, surrender peacefully, or I'll make you," said Sirius with a stern face. He learned this from his father and it seems to work-.
"Hahahahaha. Good try, kid. With that childish face of yours, no one will be intimidated by it," he laughed, increasing Sirius's annoyance.
Even coming here, he asked his father for permission to use his battle mode and the damn blonde went so far as to keep a seal on it to stop his Battle Mode from activating.
'Stupid blonde and his seals' internally cursed Sirius.
"That's it. You are a dead man," said Sirius and with his sword in hand, launched towards the laughing fool. The man proved his battle experience by jumping back and throwing his reaper.
"I may be a thug, but I am well trained and an expert in using my reaper. Do you think you can come here and go without any repercussions?" He asked in a cold tone. His reaper filling with a red glow.
"My name is Crux and this is my reaper, the blood reaper." He said in a greater than thou tone and Sirius stared at the reaper.
His attitude annoyed him. He can't hold his anger and stared at the reaper the fool was flaunting about in rage.
His cerulean blues akin to his father changed. They changed into sickly purples with a black vertical slit in the middle. Everything changed for Sirius.
He can see everything more clearly. He can see the red glow around the reaper and its hunger for blood. He doesn't know how, but he can, just see it.
'Wha- what is this? How can I see this clearly? Is this how Tou-chan feels when he uses his Sharingan?' Thought Sirius.
He knew how the Sharingan can be awakened. When a user goes through a powerful emotional condition with regards to a person precious to them, their brain releases a special form of chakra that affects the optic nerves, transforming the eyes into Sharingan.
Naruto also explained this to Sirius when asked. Naruto himself didn't know how he got the Sharingan. He just awakened them out of the blue one day after coming here.
Naruto also mentioned about a possibility of Sirius having one of the Dōjutsu(eye techniques) but they didn't experiment on it till now as his father considered him too young.
Sirius's mind went through a plethora of thoughts in an instant and when he felt something coming towards him, his body moved and dodged the reaper that was coming in autopilot.
"You have some nerve not listening to me while I talk, brat," said the Crux and launched at Sirius again.
"You have some nerve attacking me when I was thinking about something important," Said Sirius, looking up for the first time after getting his new eyes. His purple eyes bore straight into Crux's dark once.
He was petrified in an instant by the amount of hatred and malice those eyes gave off. He froze in place, unable to move his body as his motor functions stopped working because of the fear.
"Wind Style: Gale Palm Justu," said Sirius and a large gust of wind swept him away from the tent and took the tent with him. All the members of the thug's gang were still sleeping, not knowing what was happening.
Sirius tied them with a thick rope so they couldn't escape even if they woke up and went to meet with his father.