Chapter 26: Ch.26 This is Too Cautious!
Control or fusion?
Shinji was startled at first, then quickly realized that his Susanoo Tomoshibi might allow him to bypass the surgical process and use dojutsu to fuse the powers of both pairs of eyes.
At the same time, this gave him a clear understanding of the distinction between "control" and "fusion" in the context of Susanoo Tomoshibi.
These were two entirely different concepts!
"Control" referred to using the second pair of empty eye sockets to accommodate a second pair of eyes, thereby gaining part of the eye's dojutsu or some of its powers.
This was Shinji's current state.
Usually, in the control state, one cannot access the full power of the second pair of eyes.
This made sense—after all, the second pair of eyes belonged to someone else, and a certain amount of rejection or incompatibility was inevitable.
How much power could be drawn from the second pair of eyes depended on the strength of one's own eyes.
For example, since both were Mangekyō Sharingan, Shinji could only manage to draw about fifty percent of the power from Fugaku's Mangekyō Sharingan.
If Shinji possessed an Eternal Mangekyō Sharingan, he could harness about seventy percent of the power of a regular Mangekyō.