Itachi was calm and insightful, showing noticeable maturity and knowledge on how to deal with every situation. For all his accomplishments, talent, and fame, Itachi was a rather humble man. Never arrogant about his own abilities nor underestimating others, most things he said would be unbiased and accurate. If an opponent exceeded his expectations or posed a legitimate challenge to him or his allies, Itachi would freely admit it. Shisui was a very humble and down-to-earth individual. He was never arrogant about his own talent or accomplishments, yet was not above telling others when they made mistakes. At the same time, he was open-minded, never stubbornly believing in one ideal solely and strove to see that unique nature of current situation before him. Shisui was also a deeply compassionate man, even to enemies. He was also shown to be very perceptive and intuitive even from a young age, able to see through the emotional nature of others and likewise able to notice the smallest details around him.

Your friends, Shisui and Itachi are hiding their romantic relationship from everyone.