If you are looking for the After War Gundam X: Under the Moonlight manga character, please see Marco.
Marco Morassim (マルコ・モラシム) is a minor character appearing in Mobile Suit Gundam SEED.
The commander of a ZAFT submarine carrier force assigned to the Carpentaria Base. After Rau Le Creuset requests his aid in the pursuit of the Archangel, Morassim becomes determined to outdo the upstart Le Creuset by destroying the enemy ship himself. This veteran soldier often enters battle as a mobile suit pilot, and he's equally adept at the controls of the aerial DINN and the underwater ZnO types.
On April 10th, C.E. 70, Morassim, piloting a YF-3A GINN FEMWS, led a team of three UWMF/S-1 GINN WASP Type against the OMNI Enforcer's 21st Anti-Submarine Warfare Fleet in the Coral Sea. Morassim's team easily wiped out the 21st ASW Fleet, leaving only one survivor: Jane Houston, then a helicopter pilot.
After the apparent death of Andrew Waltfeld, Rau Le Creuset sent a video message to Morassim requesting for his assistance in hunting down the Archangel. Morassim saw this as a challenge and became determined to destroy the Archangel by himself.
He soon launched an attack on the Archangel in the Red Sea, leading a team consisting of two DINNs, one of which he personally piloted, and two GOOhNs. Though they initially held the advantage, both of the GOOhNs were destroyed by Kira Yamato in the Strike Gundam, the Archangel destroyed one of the DINNs, and his own DINN was damaged by Mu La Flaga's Skygrasper, forcing him to retreat.
Days after, he launched another attack on the Archangel, confronting the Sword Strike Gundam in the ocean with the new UMF-5 ZnO. Initially, the ZnO overwhelmed the Strike Gundam with its superior power. However, as Morassim grabbed onto the Strike and tried to finish it off by firing the phonon maser cannons at point-blank range, Kira stabbed his Armor Schneider knives into the cannons and tossed the ZnO aside. The ZnO then exploded, killing him.