The Soul Brothers (ソウルブラザー・Sōruburazā), or The Elite Four (暗黒四天王・Ankoku Shitennō, lit. Four Dark Heavenly Kings), is a group that appears multiple times in the Higurashi franchise, mostly in the after parties and other comic scenarios. They primarily engage in lewd fantasies. They are:
Visual Novel
The Soul Brothers were first introduced in the mini-game Renapan, available as a bonus of Onikakushi-hen but removed in Mangagamer's version. At this time, the only members were Keiichi, Tomitake and Ōishi; Irie joined them later after the introduction of his character.
They later appear during Himatsubushi-hen's after party, assisting K's ultimate form and protected by the cover of darkness.
Their last appearance in the games is in the Batsukoishi-hen chapter of Rei.
Anime
During Higurashi Rei, this group wants to become more popular with girls by using sacred trunks that make anyone who wear them for three hours become popular with girls.
When they work together they are almost comically "invincible"; however, lust invariably divides and defeats them.