Ensign Marcel was a member of the crew of Enterprise NX-01 during its mission in the Delphic Expanse in 2154.
In that year, Marcel was one of a number of crewmembers killed in a Xindi attack in the Azati Prime system. (ENT: "Azati Prime", "The Forgotten")
This character was only mentioned in dialogue.
The novel Last Full Measure gives him the first name "Felipe".