Sergio, referred to as Jordan at one point in the English dub, is Nico and West's father. The name Sergio is likely a homage to Sergio Leone, an Italian film director well-known for producing several notable western films.
Sergio is first seen when Yusei Fudo arrives to Crash Town, as he and two other slaves are trying to escape from the mountain. However, they are unsuccessful, and two members from Malcolm's gang find them. Sergio then throws a pendant to the top of the cliff, which lands near Yusei. He is electrocuted several times by the members of Malcolm's gang, and is then dragged back to the mountain.
Later fortunately, Sergio is reunited with his children, West and Nico, and meets Kalin Kessler. The four of them try to escape in a mine car. When pursuers from Malcolm's gang appear, he sacrifices himself to stop them by jumping to a track switch and using it to divert the gang members. Weakened by the shocks from his collar, he silently entrusts Kalin to protect his children, then loses his grip and falls into the abyss of the mines. In the dubbed version, he is not shown falling, and is implied to be still holding on. It seems that he would then be recaptured, and Jack Atlas later says that he was found and is fine.