“the violent ones.” The Hebrew is idiomatic: “the sons of violence.” This is a general idiomatic term for unlawful men such as robbers or bandits. It is not making a distinction between people who are “peaceful” and people who are “violent.” It is saying that some of the lawless among the Jews joined in the war.
“among your people will lift themselves up.” This vision is being given to Daniel, so “your people” refers to the Jews. A number of violent Jews joined with Antiochus III in his war against the young Egyptian king, Ptolemy V Epiphanes (Josephus, Antiquities of the Jews, 12.3.3).
“but they will fail.” The more literal Hebrew is “but they will fall,” but it refers to them failing. This is a very accurate piece of history, because although Antiochus III the Great had great success against Ptolemy, and gained much territory, and was joined in the war by some violent Jews, the Jews suffered for it. Although the Egyptian forces of Ptolemy led by general Scopas ultimately lost the war, it was not before he “punished the leaders of Jerusalem and Judah who rebelled against the Ptolemaic government (Stephen Miller, New American Commentary: Daniel).