Biography
Marco is the self-proclaimed comic relief; in several books, he states it's a responsibility. He's also the one who coined the word "Animorphs", a portmanteau of "animal morphers". Marco's sense of strategy proves essential to the Animorphs' missions, although his methods can be somewhat ruthless, tending towards philosophy of the end justifying the means. He is slightly conceited about his good looks, dubbing himself the "cute Animorph", but he is self-conscious about his height. He and Jake have been best friends since they were babies.
Marco is reluctant to fight because he knows that his father would be devastated by his death. He also argues that they are simply kids and that this is not their battle. When he coins the phrase "Animorphs", he describes the group as "idiot teenagers with a death wish". However, he also has a strong sense of loyalty, and says that he will fight to free Jake's brother, Tom. He announces that he is quitting in #5, but when he sees his mother is a Controller, he vows to continue on fighting until she is free.
Marco's dad is Peter, who lost interest in life for two years after the supposed death of Marco's mother, Eva, a Latino immigrant to United States. In reality, she was infested by Visser One roughly two and a half years prior to the series, and her death in a boating accident was faked as a way to get her off the planet. Throughout most of the series, Marco battles with himself about her fate, debating whether he should he kill her or try to set her free. He comes very close to killing her in several books, until he finally frees her in The Revelation. Marco's father was uninformed about the true whereabouts and status of his wife until that same book, when he is finally told the truth and is the first of the Animorphs' relatives to join the war effort.
Like Rachel, Marco has a bit of a dark side, which shows up in his (at times) very cold and ruthless schemes. Marco is often focused on the "big picture" ( ultimately destroying the Yeerks), sometimes at the cost of the "little" things (his mother, for example). He isn't entirely comfortable with this aspect of himself, but has embraced it as necessary to the war effort. He also struggles between the dream of his mother returning to normalcy, and moving on, accepting her for dead. This conflict is revealed in The Proposal. In #10: The Android, he develops a lust for gruesome revenge against the Yeerks, and admits to enjoying being violent (for example, he worries Ax when he tries to kill a beetle in spider morph), even though he constantly derides Rachel's violent habits.
Marco prides himself on an ability to see the clear path from Point A to Point B - to chart the most effective plan of action, with morals or values being secondary concerns. This is not to say he is immoral, as he is able to factor in these values and alter the plan accordingly - but he does have the ability to see what needs to be done to achieve goals. In this way, he is extremely valuable strategically.
At the end of the series, Marco has a flourishing post-war life; he has become a celebrity, starring in TV shows, giving interviews, and becoming the unofficial spokesperson for the Animorphs. He enjoys the playboy lifestyle, although he admits to being "bored out of his mind" and does not hesitate to give it all up and join Jake in a possibly suicidal mission to rescue Ax. He is the final narrator of the series.
Marco is also the only Animorph in the series without a main love interest, though not for lack of trying.
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