Captain Moroni first appears in Alma 43:16:
Now, the leader of the Nephites, or the man who had been appointed to be the chief captain over the Nephites – now the chief captain took the command of all the armies of the Nephites – and his name was Moroni
And Moroni was a strong and a mighty man; he was a man of a perfect understanding; yea, a man that did not delight in bloodshed; a man whose soul did joy in the liberty and the freedom of his country, and his brethren from bondage and slavery; Yea, a man whose heart did swell with thanksgiving to his God, for the many privileges and blessings which he bestowed upon his people; a man who did labor exceedingly for the welfare and safety of his people.
I am Moroni, your chief captain. I seek not for power, but to pull it down. I seek not for honor of the world, but for the glory of my God, and the freedom and welfare of my country.
Moroni is best known for creating the title of liberty found in Alma 46:12,
In memory of our God, our religion, and freedom, and our peace, our wives, and our children
Moroni had thus gained a victory over one of the greatest of the armies of the Lamanites, and had obtained possession of the city of Mulek, which was one of the strongest holds of the Lamanites in the land of Nephi; and thus he had also built a stronghold to retain his prisoners.
Moroni was also a patriot who fought to keep in own government in-line starting from Alma 59:13,
And it came to pass that Moroni was angry with the government, because of their indifference concerning the freedom of their country.
[Moroni] did also mourn exceedingly . . . because of those who had rebelled against their country and also their God . . . Moroni took a small number of men . . . and took his march towards the land of Gideon. And he did raise the standard of liberty in whatsoever place he did enter, and gained whatsoever force he could in all his march towards the land of Gideon . . . thousands did flock unto his standard, and did take up their swords in the defence of their freedom . . . they became exceedingly strong, even stronger than . . . those dissenters who had driven the freemen out of the land of Zarahemla and had taken possession of the land . . . and went forth against the city . . . [and] did come to battle . . . Pahoran was restored to his judgment-seat.