Marcus Rush is a fictional character from the Robotech series. He appears briefly in the last issue of Robotech: Prelude to the Shadow Chronicles and becomes a major character in the movie Robotech: The Shadow Chronicles as one of the main protagonists.
Marcus' comments were likely in reference the Invid, not Zentraedi and other allied aliens. However, the fact that the Zentraedi nearly wiped out humanity in the First Robotech War led many humans to hold grudges against them. He hates the Invid because his sister, Marlene, was killed during the failed assault by the 21st Mars Division against the Invid on Earth in 2042. The only thing that he has as a memory of her is a hologram pendent left to him by Marlene and her fiancé, Scott Bernard, whom he believed was also lost in the destruction of the Mars fleet. He uses the pendent to keep a running tally of the Invid that he's killed, placing a mark on the pendent for each kill. However, Scott Bernard survives and eventually reaches Moon Base ALUCE after the Reflex Point. However, Marcus' joy at seeing Scott again is tempered when Scott confirms that Marlene did not survive.
In Robotech: The Shadow Chronicles Marcus serves in Wolf Squadron during the Battle of Reflex Point in 2044. However, the death of Commander Daryl Taylor during the battle and the heavy losses sustained by the Robotech Expeditionary Force (REF) results in the merging of Wolf and Skull squadrons, which places Marcus and Alex under the command of Maia Sterling. Upon the discovery that Scott Bernard has befriended Ariel, the daughter of the Invid Regess, Marcus attacks Scott and probably would have seriously injured or killed him if Alex had not intervened. Scott tries to explain that Ariel choose to stay behind with him and that she is not the enemy but rather that she is trying to warn the REF that a new threat, "The Children of the Shadow," is about to manifest itself. However, Scott refuses to believe him and maintains that all Invid are evil and must be destroyed.
When the Haydonites, who are later revealed to be the threat that Ariel warned of, turn on the REF, Skull Squadron is ordered is ordered to head to Liberty, and change to fighters that don't incorporate Haydonite technology but are pursued by Haydonite fighters. Alex Romero tries to engage them but his syncro-cannon, crippled by the Haydonite attack, malfunctions and his fighter becomes stalled. Despite the pleas of Maia and Marcus for Alex to eject, he flies into the enemy squadron as his fighter explodes, destroying himself and all of the enemy fighters. Maia is visibly upset by Alex's sacrifice while Marcus, who was Alex's best friend, is completely devastated. After arriving at Space Station Liberty, Skull Squadron acquires Super-Shadow fighters that have not had any Shadow technology installed yet. The squad immediately engages the Haydonites in hopes of holding them off long enough for Liberty's personnel to be evacuated to the colony ship Ark Angel and for Vince Grant and Scott Bernard to rig the remaining Neutron-S missiles on Liberty for detonation.
During the battle, Maia's fighter is damaged and she is forced to eject. Marcus uses his fighters' robotic arms to grab Maia's capsule and throw it towards the Ark Angel as it prepares to fold jump. Marcus, deciding he has nothing left to live for, holds down his weapon triggers and launches a suicide run against the Haydonites to hold them off long enough for the Ark Angel to escape. Just before the Neutron-S missiles detonate, Ariel uses her teleportation ability to save Marcus' life. Marcus has a vision of his sister Marlene, who tells him that it is not his time to die. Marcus pleads for her not to go but then awakens onboard the Ark Angel with Ariel by his side. Marcus, surprised to be alive, almost angrily asks Ariel why she saved his life since he has only hatred for the Invid. Ariel responds that "hatred can only breed more hatred. It is not what we seek... any of us."
At the end of the movie, Maia thanks Marcus for saving her life. Marcus remains despondent over the fact that everyone he has loved or befriended - his sister (Marlene Rush), his commanding officer (Daryl Taylor), and his best friend (Alex Romero) - have been taken by war. Maia, whose family was aboard the SDF-3 (which is lost in space), puts her head on his shoulder and the two look out a window as the Ark Angel flies over Earth, a planet which neither of them has ever seen until now.