Living with the Blacks was surprisingly good, Regulus constantly made sure his baby brother was okay, Sirius liked tickling and playing with him, while Walburga fed, changed, and loved him.
His father, Orion Black, barely made an appearance, focusing on politics rather than family.
During these rather bland two years, he only focused on harnessing and increasing his control over his magic, he didn't try to cast any spells at an early age in case he stunted his growth.
While he acted his body's age, he wasn't afraid to show his genius. He started walking at seven months and talking with the occasional stutter or slur just after his first birthday.
His first bout of accidental magic was when he apparated onto his father's lap during a Wizengamot meeting.
Now, two years old, he sits on his rocking chair reading a book on beginner spells.
Hearing the door open, he looks up to see Sirius, "Siri", he says as he runs to cuddle his brother.
Sirius started Hogwarts a year ago and hasn't been home for many months.
"Archie, I see your running now. you get bigger every time I see you", While Sirius despised the majority of his family for their pureblood traditions, he had a deep love for his youngest brother.
Picking up his little brother, he sits on the bed, "I heard from mother that you started reading and writing already"
Arcturus nods, "I love reading,.. BROTHER!", he suddenly shouts before jumping off the bed, "Look what I can do"
Sirius' jaw hits the floor as he sees the small boys hair, eyes, and skin turn various colors, "You're a Metamorphmagus"
A prideful smile washes over the little boy's face, "Mother started spoiling me and getting me lots of books on whatever subject I want"
After a few more minutes of talking, a house-elf pops in and notify's them that dinner is ready.
Sitting in a dimly lit room around a large pitch-black table, Arcturus eats his food while talking with his family, "Father, may I ask a question?"
Orion swallows his food before looking at his youngest, "as long as it's not something idiotic"
"Well, I was thinking, why is it so important to be a Slytherin, surely if I or my brother were in one of the other houses, it would provide us with information and allow us to keep an eye on our enemies"
The room went silent, everyone around the table knew the boy had a point but didn't know how Orion would react to the question.
"You have made a valid point, but it's tradition to be a Slytherin in this house, the only other house I will accept from my sons is becoming a Ravenclaw", the older man said while sending a mild glare ate his oldest for being sent to Gryffindor.
No one expected the rebuttal of the young boy, "But isn't being the most powerful family in Britain more important than some silly tradition about a school, We are the richest magical family in perhaps the world, but that may not last forever, as a great man once said, keep your friends close and your enemies closer"
Once again, silence filled the room before Walburga broke it with a stifled laugh, "Well, at least we know which of our sons will take our family seat on the Wizengamot"
This caused the rest of the family to break into smiles except for Orion who was thinking about the boy's words.
Archie returned to his room after dinner, "Thank fuck that's over with", he murmurs before flopping onto his bed.
Sitting with his legs crossed and his eyes closed, he meditates on clearing his mind and decides it's about time he starts learning Occlumency since he's already read several books on it, and has a fairly good idea of what he want's his mind to look like when someone tries to look into it.
-- Two Years later --
Sitting in the same position, a taller Arcturus opens his eyes with a maniacal grin, "two long fucking years and I finally mastered the art of Occlumency"
Getting dressed in finely tailored clothing, he wears the new business suit his father bought him.
Leaving his room, he meets his father at the front door, "I still can't believe you're going to the Wizengamot meeting with father", Sirius says while leaning against the wall.
"Someone has to take over after father once he dies, Regulus is too tame while you have the charisma of a mutt", he says while grinning at his brother.
It had been confirmed that while Arcturus wouldn't inherit the house, he would inherit the Wizengamot seat and the family seat on the Hogwarts Board of Governors when he turns seventeen.
After saying his goodbyes, he apparates away with his father.