Split infinitives occur when additional words are included between to and the verb in an infinitive. Many readers find a single adverb splitting the infinitive to be acceptable, but this practice should be avoided in formal writing.
When he was 11 years old, Itachi was also under orders from his father to enroll in the Anbu half a year later. Itachi was praised highly by Fugaku, who spent most of his time grooming Itachi to inherit the title of leader of the Uchiha, and hence inadvertently neglected his younger son.
Itachi Uchiha gained the Mangekyo Sharingan by killing his best friend, Shisui Uchiha. With the Mangekyo Sharingan, Itachi is able to use the three most powerful jutsu of the Uchiha clan. The first is Tsukuyomi, a powerful genjutsu. This jutsu comes out of and puts strain on the left eye.