After learning the Jutsu she could reverse engineer from her inherited memories, Natsume began to focus on her destructive Jutsu from months ago. Initially when she used it the first time, she felt as if she was being guided by a subconscious force. Based on the vague descriptions from her memories, it seemed to match a kekkei genkai. However, she didn't know of any combination of Fire and Yin release.
Apparently, Senju Hashirama's signature Wood release was influenced by his extraordinary Yang chakra. Since Wood release is non-existent in the current ninja world as far as Natsume knows, it's likely that it's more than just a kekkei genkai. This can also be supported by a few other examples, Mud release is also a kekkei genkai of Water and Earth release, but not even a fraction of the strength. As for the Fire and Earth release kekkei genkai, it is represented in different ways, like quicklime, corrosive acid, or the most notable, Lava.
If there are variations within a kekkei genkai, perhaps she too has a variant based on her Yin chakra. She attempted to perform a simultaneous nature transformation of Fire and Earth release, but the chakra was unstable and exploded. She frowned but didn't give up, because at the moment of fusion, she felt something familiar. She activated her sharingan and continued practicing. She observed her nature transformations to their most minute details in order to discover the correct path.
After several failures, Natsume laid on her back staring at the pink sky. The sun was already rising and it was time for her to go see Kono and Madara. However, she was still trying to catch her breath. Not only was nature transformation of two different natures difficult, running away from the explosions was also very tiring. However, she had a bright smile on her face. In a corner of the training arena was a spot on the ground covered in black rock.
'Partial success? That sounds about right. But was that really Lava release?' Natsume wondered. The flames she created were thick and had volume. However, it was more leaning toward fire than earth. She couldn't quite figure out what it was exactly but perhaps after succeeding she would be able to identify it.
When she finally caught her breath, she put the matter of Jutsu on pause and thought about another big issue in the future ninja world— the tailed beasts. Hashirama single handedly defeated all the tailed beasts in a duel and distributed them to the other villages. Natsume didn't need a moment to consider it before she knew how bad of an idea that was. She held her head while walking back and thought that the future of her clan could not be left to Hashirama.
Although he did not have ill intentions toward the Uchiha, he was simply too much of an idealist. She didn't think anyone born in this era would make such a decision, unless they were the reincarnation of the world's biggest optimist… Asura's chakra was likely very influential in Hashirama's growth. Natsume suddenly stopped and had a strange feeling.
'Will I end up the same way?' She thought about how she was also the reincarnation of someone, however, she shook her head at that possibility. The difference was self-awareness. Natsume's past life did not have chakra, and Natsume herself was fully aware of the memories. Although they may affect her subtly, it would not change her in any drastic ways from her core beliefs.
'That being said… I really want to try Ichiraku Ramen…' Her mouth watered at the idea.
"Natsume, you're late today." Kono said with a frown as she held Madara in her arms. "How was training?"
"I had a small success." The smile on her face was apparent. She didn't realize it herself, but Natsume became a lot more cheerful when she inherited memories of her past life. Although she was always a kind and thoughtful person, the peace and knowledge that came from her memories gave her a sense of security. "How is Madara-kun doing today?"
"Tajima came to see him this morning—pssh," Kono couldn't keep herself from laughing at the thought, "Madara cried the moment he was picked up. And when Tajima set him down, he stopped crying. He came to me worried that his son was broken—ha ha ha!"
Natsume smiled and giggled at the visual. Tajima was a very serious man, but in front of his son and wife, he couldn't get an advantage. Spending time together with Kono and Madara was always a good time, despite how needy a newborn was. Natsume began to wonder why there were no memories about Madara's mother. She worried that perhaps Kono's end was another life changing moment for Madara. She already promised to protect the clan, and that naturally included her best friend, Kono.
Over the next month, snowing or not, Natsume would go to the training field and practice her Jutsu. It wasn't after a whole month of practice that she was finally able to see results. A line of sticky gel-like white flames were plastered to a rock. Despite the fires lasting for several hours, surrounded by snow, they refused to go out. Natsume stared at the sticky flames that burned and yet also flowed like liquid and came up with a close estimation based on her memories.
'Napalm?' Was the only thing she could think of. According to her inherited memories, there was a lethal type of mixture that could create explosions and flames that stuck to flesh and burned until the fuel was consumed. Comparing it to Lava, it was far less destructive, however, it had its own advantages too. She was reminded of one of the Mangekyou Sharingan's abilities from her memories—Amaterasu. They shared similarities in how they refused to be extinguished by normal means.
Although it wasn't Lava itself, the flames seemed to get hot enough to turn nearby earth into Lava. This gave Natsume some ideas and now that she mastered the sensation of using Fire and Earth release together, she would attempt to do the most basic Lava release instead of her unique transformation. However, these peaceful days were destined to not continue.
"All active and inactive Uchiha warriors, report to the clan commons!" Tajima's loud voice sounded out across the complex.