Senju Shinobi dies during the third Shinobi war and gets reincarnated as itama senju in the warring clans era with the skills Copy and devour. Also since it's his own skills he can't be controlled by the skills 
Copy: A copying ability that allows user to copy whole living or dead bodies and inorganic objects. The copied objects or copied people also completely copies all the abilities of the objects or people that was copied including chakra 
Devour: A ability that allows user to create a small black hole from there hand and just needs a small amount to absorb anything to gain its abilities, skills, techniques, appearance and chakra

Tobirama, now a formidable young shinobi, took a formal interest in Itama's "prodigious" intellect. He began teaching him formal ninjutsu theory, fuinjutsu basics, and tactical planning. Itama, using his future knowledge and **Devour**-enhanced comprehension, absorbed it all at a staggering rate. He would ask questions that were decades ahead of their time, about chakra network optimization, about the nature of the soul.


Tobirama was both intrigued and slightly unnerved. "Your mind works like a perfect scroll, brother," he once said. "You see the pattern in everything." Itama simply nodded, using Tobirama's own lessons to better hide the terrifying extent of his true abilities.


Chapter 12 - Tobirama’s Protege