Romeo and Kevin are twins so they both look almost exactly alike. The differences for Romeo though is that he has shorter hair with long side swept bangs that cover one eye.
Romeo comes and goes as he please and he doesn't care about who or what he interrupts. He can also be pretty rude and perverted, always hitting on the girls of the crews. He tries to be 'charming' but in actuality he's just annoying. He's persistent and demanding, always trying to get what he wants. But there is an upside to him, when called he always answers so the crews can count on him as a last resort helper.
When they were young Kevin accidentally killed Romeo. He soon became the Sheer King and at a distance saw his brother grow up. But as far as Kevin knew his brother had already passed on. Then when Dreyus stumbled upon romeo's mansion the truth came out that Romeo was still around. Very briefly at one point Romeo fully came back as his six year old self...that didn't turn out so well...
Because Romeo is the Sheer King (king of all ghosts) he has abilities that not all ghosts have. He can appear at any place of his choice and can materialise and de-materialise (become solid and see-through). He can also turn completely invisible.
He is Kevin's identical twin and Fallen's younger brother.