Doing the lord's work.
A modder who goes by Nerante on Nexus Mods has been working through various Naruto games, adding in one small yet very cool feature—a different Magenkyou Sharingan for Itachi Uchiha.
For those of you who don't know, a Magenkyou Sharingan is a special ability unique to the Uchiha clan in Naruto. With only a few shinobi unlocking the ability, its effects can vary from person to person. Itachi Uchiha is one of the few people shown with this ability. With this, he can use Tsukuyomi in his left eye, which distorts a victim's perception of time, and his right eye can use Amaterasu, which is basically a fire that cannot be extinguished. These are some of the strongest abilities in the series, so strong that the character had to be killed off by a mysterious disease in the manga.
"This mod changes the eyes of Itachi with his father's [Fugaku Uchiha] Magenkyou Sharingan," according to the description of every mod so far. So far, five games have this mod: Naruto Shippuden: Ultimate Ninja Storm 2 and 4, Naruto Ultimate Ninja Storm 3, Naruto Ultimate Ninja Storm Revolution, and Naruto x Boruto Ultimate Ninja Storm Connections.
So, apart from looking cool, it's a bit confusing why this mod exists because Itachi definitely doesn't need to be buffed. I may not be able to figure it out, but that doesn't mean this mod shouldn't exist—sometimes 'why not' is reason enough.
It's also not actually confirmed in the manga that Fugaku Uchiha has a Mangenkyou Sharingan, which is only referenced very quickly in an anime-only scene. It's pretty much a mystery as to what his ability is, although some theorise that it allows Fugaku to predict the future of various choices he makes.
If you watch the YouTube video that Nerante links on most of the mod pages, it shows a fight between the modded Itachi and Delta. Not much has changed as Itachi still uses his Tsukuyomi and other abilities, such as using a swarm of crows mid-fight to teleport around the arena. I couldn't get a good look at his eyes to see if they really did resemble his father's, but during Itachi's final move, his eyes seem to revert back to his original Mangenkyou Sharingan, but that's probably due to it being part of a finishing move animation.
Luckily, using the mod isn't as complicated as figuring out why it exists. Under installation, Nerante just explains, "Put the data_win32 folder in the game directory; play, have fun." So, if you ever wondered what it would be like for Itachi to have his dad's eyes, then I guess this is your chance to go check it out.
