Root

After absorbing all the information he'd collected and made sure none of it was lost, Shikamaru infiltrated the Hatake, Sarutobi and Shimura, clans, There he obtained Knowledge on Summoning and Seals as well as a more thorough interpretation of the Villages History.

But what was the most significant discovery was the Shimura clan, Here he found out about ROOT, the darkness of Konoha, He had known through his shadow sense that there was a group of ANBU with little to No emotions with Blank masks, but there were some records in the clan that proved their existence. He would have to infiltrate the organisation as well.

He infiltrated the Uzumaki compound and mask temple using his Shadow Step which would not have been possible otherwise as the mixture was blood locked using seals, here he didn't find much besides some books on sealing and about the Uzumaki history.

when he entered the Senju compound he found intricate knowledge on healing, Sage mode, Summoning and A whole Library on Seals and Seal theory, which most probably belonged to Mito Uzumaki. He was intrigued by the little he skimmed through on sealing and decided to Infiltrate the Namikaze house, It was destroyed after the Nine-tails attack but it still wasn't accessible due to the blood seals around the compound so as he entered and looked through the rubble he found more on sealing and some books from Hidden Whirlpool, It was stated in the Shimura records that Minato Namikaze had married Kushina Uzumaki and had a son named Naruto Uzumaki who is the current Jinchuriki to the Nine-tailed Fox after Mito and Kushina Uzumaki. After looking at the pictures, he deduced that the man with the Golden Cloak was Naruto and he'd have to factor him into the plans as well.