Shitsuo Heiwajima is another alternate of Shizuo Heiwajima. He's just basically a kind of parody due to the fact that his
seiyuu (Japanese voice actor), Daisuke Ono, also voices Sebastian Michaelis, a butler, from Kuroshitsuji.
His personalities are mainly very loyal like any butler towards serving their masters. Shitsuo's is usually depicted as Hibiya "Subarashi" Orihara's butler. However in some cases, he can also be serving Sakuraya instead.
Some also believe Shitsuo as a dark side of Shizuo. In these translations, Shitsuo is shown to be a sadist and has a sick personality.
Shitsuo's eye colour is gold with a hint of green or grey (Which can be considered hazel). He is dressed in a butler outfit, much like Sebastian Michaelis. He is usually depicted wearing white or black gloves, a black suit, white button-up shirt, and glasses.
Shitsuo is most commonly paired with Sakuraya and they are portrayed, usually, as a more gentle couple. In this type of relationship, Shitsuo is Sakaruya's family butler that has served him for his entire life. As a result, Shitsuo is extremely loyal to Sakuraya and does everything he can to make him comfortable, which can lead to Sakuraya feeling guilty. Many times, with this pairing, the two are shown as forbidden lovers because of class differences or arranged marriages, creating a sort of Romeo-Juliet type relationship.