SilverFlame

Exactly, and the sheer amount of Karma he can get by doing so is too tempting to let go of... he doesn't need it for exchanging again as he isn't planning to die, but the passive effects are enough for him...

Excellent, I was waiting for someone to ask this. Thanks :) So why didn't he directly try to replace Nagato? The answer is quite straightforward actually; he lacks the confidence in doing so silently like he did with Yahiko. The main reason is, what if he Nagato somehow activates the Gedo statue? What if Madara notices someone scheming to get his eyes? Thing is he doesn't know... and what he doesn't have a 100% confident in, its better not to try yet... at least not before he gets his hands on Madara's samples...

No… Darui started learing from Raikage at 4-5

His current strength is that of a low level Kage (purely based on stats). For the childhood arc, I mean there will be war soon and its done after that :) As for your question about showing off, like I commented in the last chapter, it will be coming soon too...

Well, I have a confession I guess. When I wrote it, I was thinking like... not everyone is like our MC to have memories since birth, right? so for the most part the first few years will be just personal memories of a kid which will be filtered by the A.I chip... hence, he will ultimately be left with close to 10 years worth of memories... However, now I realize I made such a horrible job of putting it into words...

Till now everything he's done is from the shadows, but soon that will start to change... and these will come...

This is correct. According to Wiki, Yahiko dies at the age of 17-18 which is like 3 years from the current time. So, that would put his age at 14 years. In addition, at this time, the trio Konan, Yahiko and Nagato would have become full fledged Ame shinobi. The action of MC here is just killing a ninja from an enemy village. Also, as Akisu wrote, he is aiming to become more powerful himself by awakening Rinnegan, hence not needing a reason for Nagato's favor... Anyway, thanks for bringing these points up... they really help others too... :)

Zero-Tails is a bit different... what he is thinking of creating is the copy of Five-Tails but without a soul ... like a shell on which he can use his soul descent technique...

Not yet...

Okay, let me answer these... 1. Chakra IS Energy, as that is how it is introduced; it is created by melding Physical Energy and Spiritual Energy. Now, Rasengan on the other hand is a Ninjutsu that takes the Shape Transformation of Chakra to the limits, so much so that it uses the rotational force generated by constantly rotating chakra to do Physical damage. However, that doesn't make Chakra a Physical substance, it's still energy. 2. The added weight technique is indeed adding gravity; by increasing gravity, it increases the density of the solid. Also, the sentence starts with a "like" so it's not actually turning stone to metal, it's like.