The captain only appears for an episode or two, but his significance lies in the fact that he transports Team Urameshi to the Dark Tournament via his boat and provides them with their first test of preparation of what is to come.

Urameshi Yusuke, 14 years of age, is about as troublesome and violent as teenagers come. He is constantly ditching school, causing trouble, and getting into numerous fights everyday. One day however, he does the unexpected, sacrificing himself to save a young child. Such an action, was never ever expected, especially coming from someone as troublesome as Urameshi Yusuke. The afterlife is not prepared for Yusuke, as they never thought he would make such a sacrifice. Nowhere to go, and dead, Yusuke becomes a ghost and must earn his way back into existence. 
Yusuke is "employed" by Koenma, who is in charge while his father and ruler of the afterlife, King Enma, is away. Under Koenma's command, Yusuke helps to stop menacing demons that threaten the lives of people everywhere; whether by stealing priceless and invaluable items and destructive weapons, or by wreaking havoc on humans everywhere. 
Throughout Yusuke's journey, he is usually joined by; his arch-rival, and local bully, Kuwabara Kazuma. He is also joined by two demons named Hiei and Kurama, whom are ex-convicts of the afterlife that managed to escape from Koenma. 
This group of unlikely allies goes on to participate and struggle in battles that have outcomes that determine the fate of humanity! 
(Source: AniDB)

__Non-Anime Roles:__ 
Bernhardt in "Der Langrisser" (VG) (Japanese)  
Chaos in "Langrisser III" (VG) (Japanese)  
Fahvel in "Langrisser III" (VG) (Japanese) 

Ayrton Cardoso was a Brazilian actor and voice actor.

Yusuke Urameshi was a tough teen delinquent until one selfless act changed his life...by ending it. When he died saving a little kid from a speeding car, the afterlife didn't know what to do with him, so it gave him a second chance at life. Now, Yusuke is a ghost with a mission, performing good deeds at the behest of Botan, the ferrywoman of the River Styx, and Koenma, the pacifier-sucking judge of the dead.
 
(Source: Viz Media)
 
Note: Chapter count includes one extra chapter.

Senchou