Dagger's one of the performers at Noah's Ark Circus, working as a knife thrower—and he's genuinely skilled at it, never missing a shot. He's incorporated his talent into his fighting style, making those blades as much a weapon as a circus act.
When Ciel shows up undercover as "Smile," Dagger takes him under his wing and helps train him up. Despite everything going on, Dagger maintains this consistently upbeat energy throughout the manga. He's got the closest bond with Joker, though he's clearly got feelings for Beast that aren't exactly hidden. The thing is, Beast is pretty obviously more interested in Joker, which puts Dagger in that awkward position of being the third wheel.
Content compiled by AnimeList.moe from publicly available sources.
