Daniel is a not-so-normal guy in a not-particularly-normal situation. He's one of Israel's elite citizens, captured and trucked out to Babylon to add some brainpower to King Nebuchadnezzar's court. But he adds a lot more than brainpower (though he does provide that, too). What he adds is something Nebuchadnezzar didn't bargain for when he decided to kidnap the smartest and most talented members of the Israelite nobility: the prophetic judgment and guidance of God. Yep.
Daniel is pretty modest, even though he's able to accomplish great things. He's not just able to interpret Nebuchadnezzar's dreams, but also is able to tell what the first dream was without knowing beforehand. But this isn't false modesty. We get to see Daniel praying at night and receiving visions and special knowledge from God. So it becomes clear to us that Daniel's abilities are something given to him, rather than something he just happens to have. In fact, that's the big difference between Daniel and unrighteous rulers like Belshazzar and Nebuchadnezzar. Daniel is great because he knows he isn't; Belshazzar and Nebuchadnezzar aren't great, because they think that they are.
So, a big part of Daniel's character is his humility. It's what allows him to thrive and to keep advancing his status in the kingdom. It's precisely because he doesn't care about worldly success that he is allowed to become so successful. He's a righteous man, and that's something that sets him in contrast to all the people who are just time-servers, flattering the king and trying to snivel their way up the ladder of royal promotions.
The first half of the book shows Daniel as a courageous and heroic man who admirably stays true to his God and to his own principles. He helps save even the bumbling Babylonian enchanters by interpreting Nebuchadnezzar's dreams, isn't afraid to offer up negative predictions to kings, and gets to spend the night in a den full of lions because he sticks to his convictions—all of which is pretty amazing.
But we don't really get to see what's going on in Daniel's head in those parts of the book (the first six chapters). We just see the role he's playing in the stories and learn about the kind of guy he is from the actions he takes. So, it's sort of a shock when, in the last six chapters, we do get to take a long, intense look into Daniel's inner life. It turns out to be really weird, kind of like being John Malkovich. It's not quite as weird as John of Patmos' inner life, but pretty weird, nevertheless. For example, Daniel doesn't just see fantastic beasts with lots of horns. He sees that one of the horns has a little human face and likes to say boastful arrogant things.
Daniel also represents a person who is atoning for the sins of his people. He, himself, is quite righteous, but he dons sackcloth and ashes and fasts to apologize to God for the disobedience of Israel as a whole. In the same way that other prophets—who have done nothing wrong—humble or even humiliate themselves to make a greater point, Daniel does penance for Israel, saying "All Israel has transgressed your law and turned aside, refusing to obey your voice. So the curse and the oath, written in the law of Moses, the servant of God, have been poured out upon us, because we sinned against you."
But Daniel isn't just ratting out his people to God. He's helping them, begging for mercy, even though he himself is basically guiltless. He's personally suffering the consequences of the guilt and trying to redeem his people along with redeeming himself. It makes the greater point that one humble and good-hearted person can manage to elevate not only his own life, but the lives of the people connected with him.
The name Daniel, by the way, means "God is my judge" in Hebrew. This is pretty appropriate, given that everyone else who tries to judge him—like the Persian satraps—ends up getting killed.