Marcos has black hair, gray eyes and bushy eyebrows.
A prankster at heart Marcos enjoys playing games and pranking people. Marcos is very proud of his heritage and was excited to get a reaper at first. Marcos dislikes his brother for being a bully to him and often wishes for retribution against him but Marcos is too scared to try anything against him. According to Cisco Marcos looked up to Gema but it was because he did not know her. Marcos also respects his father a lot and was elated to finally see him again. Marcos was extremely saddened to find out that his mother sacrificed herself for him.
The fourth child of Zeff and Mariana Elroy Marcos was born a Rainlord. This mean't that he was to become a servant at fourteen as was custom. However when the Vanguard attacked his family Marcos was killed in the crossfire. Mariana forced her reaper to release her and take on Marcos as a servant to save him.
Marcos stayed at Red Lake Castle but was him and his siblings were abducted by Melchor Blackburn. During the Siege of Marshrock all the hostages were released and that meant Marcos' release. He was moved to Moaban were it was attacked by Abolish forces. When Emiliana found invisible Abolishers in their room Marcos and his family moved to escape. They were trapped shortly after however by the Marauder of Calthos Caster. They attempted to escape but then Gohvis arrived. Gohvis took out Caster and attempted to capture the Elroys or perhaps only Emiliana. Due to Ibai's arrival the children were able to attempt an escape although they were chased by Gohvis. Emiliana pushed Marcos and Ramira out of the way predicting that Gohvis would prioritze her and leave them alone.