Raw power and persistant vs intellegent and skill

[Uchicha Macho]

- In order to prepare Izanami, which requires shared physical sensation. His only method of beating Kabuto relied entirely on him having regerative abilities.

- Kabuto could've cancelled him effortlessly considering Itachi was merely under genjutsu and not actually free from ET.

Itach had ultimate defense and offense in this final form susano but why he never use it.Why itachi did not spam his finally form susano which orichimaru call him invincible?
This is because itachi was fightning kabuto without killing him.Itachi use his edo tensi body to take the damage instead of fighting him with susano