Mike Zacharias was the squad leader of Squad Mike, a major division of the Survey Corps. A trusted soldier, he was considered humanity's second strongest soldier after Captain Levi. Mike had a remarkably good sense of smell, which allowed him to detect Titans from great distances.
Mike was a tall and well-built man. The bangs of his blond hair were parted down the middle, and he had a dark mustache and beard. Similar to Erwin Smith, Mike was almost always seen wearing a serious, calm expression. He was typically seen dressed in the standard Survey Corps uniform but also wore the Survey Corps' signature green cape during expeditions.
Mike was an acknowledged leader with a brave heart and a tactical mind. He was a loyal member of the Survey Corps and an adamant vanguard for mankind's freedom, believing humans can only lose when they stop fighting. During times of ease, Mike was shown to be a quiet man, rarely speaking unless it concerned a more serious matter. He also had a bizarre habit of "sniffing" people out when he met them. However, fellow squad leader Hange Zoë claimed he was a very capable leader, despite this strange habit which Hange claimed probably meant nothing. He also cared a great deal for his squad, as he took on a great deal of Titans to allow them more time to escape. Mike felt sorry for putting the 104th recruits in such a vulnerable position during a Titan invasion. In the end, despite his courage, Mike proved to have a breaking point. Trapped and helpless, he showed utter terror as he had been relieved of his equipment by the Beast Titan. However, he gathered his courage and raised his sword to continue the fight shortly after, but this moment of strength fell short as he could only scream in agony and horror as he was pulled apart by numerous Titans. In the end, Mike stayed true to his word to never stop fighting even when faced with overwhelming opposition.
Appearance: Mike was a tall and well-built man. The bangs of his blond hair were parted down the middle, and he had a dark mustache and beard.
Personality: Mike was an acknowledged leader with a brave heart and a tactical mind. He was a loyal member of the Survey Corps and an adamant vanguard for mankind's freedom, believing humans can only lose when they stop fighting.
Mike Zacharias in the story: Mike is among the Survey Corpsmen who leave Trost District on an expedition. Mike, Hange Zoë, and some Military Police soldiers escort Eren Yeager to the military courtroom for his trial. During this time, he takes a few moments to sniff Eren and then smirk, much to Eren's confusion.
How Mike Zacharias echoes later: As Erwin Smith contemplates his role as Commander of the Survey Corps and the lies he has told his comrades, he envisions himself standing atop a mountain of corpses of the soldiers he sent to their deaths. In Erwin's mind, Mike lies at the top of the mountain of corpses, alongside Nanaba and Gelgar, staring back at him. Later in the Battle of Shiganshina, as Erwin Smith begins to lament the dwindling hopes of his dream, Mike stands among the many fallen Survey Corps comrades in Erwin's mind, wanting to know if their deaths had meaning.
Source: Attack on Titan Wiki, available under CC BY-SA 3.0.