"Earth Grudge Fear can steal other people's hearts, granting their chakra natures and some of their abilities. But what if the stolen heart already contained the power of improved Hashirama cells with reduced activity? Could I gain the benefits while avoiding the risk of turning into wood?"
He wasted no time putting the idea into practice.
He immediately experimented on a crow.
He transplanted a second heart into the poor crow, fusing a trace amount of seventh-generation Hashirama cells with Earth Grudge Fear's black tendrils during the procedure and injecting them together.
The results were a pleasant surprise!
Not only did the crow survive without turning into wood, but its control over its newly acquired Wind Release chakra improved noticeably, and its physical capabilities rose as well!
Better still, with the improved Hashirama cells mediating between them, the two hearts coexisted in remarkable "harmony," allowing chakra to flow smoothly!
"An unexpected bonus!"
Uchiha Makoto's eyes shone as he watched the two-hearted crow flap around its cage with exceptional vigor.
"The powerful vitality and harmonizing properties of Hashirama cells perfectly compensate for the rejection and conflict caused by Earth Grudge Fear's crude transplants! And Earth Grudge Fear's properties as a 'container' give the Hashirama cells a stable, controllable environment to inhabit! A perfect match!"
The blueprint for human experimentation grew clearer in his mind.
Of course, while Uchiha Makoto had something of a mad scientist in him, he still had boundaries.
Experimenting on his fellow Konoha ninja or innocent civilians was out of the question.
So his source of "experimental materials" became foreign ninja who showed up "uninvited."
Over the past few months, Uchiha Makoto had done plenty of "dirty work" while out on missions.
He specifically targeted hostile ninja who were alone or looked like bad news.
Knock them out,