Jim Conklin or "the Tall Soldier" is the more experienced and mature soldier, particularly compared to Henry at the outset of the novel. He is confident enough not to brag or to claim that he wouldn’t "run" if things got very bad. Jim is calm and practical and usually relaxed. He even makes fun of himself and of the soldiers’ situation at times.
But, to tell you the truth, the most important thing Jim does in this story is die. Jim’s death is a HUGE DEAL for Henry, and it brings our discussion around to an important piece of The Red Badge of Courage: religious stuff.
Let’s start by thinking about Jim Conklin’s initials. J.C. Can you think of anyone else with those initials? Yes, that’s right – Jim is the resident Jesus figure here. Which means that his horrible, grisly, painful death scene probably has something to do with sacrifice or martyrdom. On closer look, you’ll find that the passage indeed has mention of "whipping," a "solemn ceremony," and "bloody hands," and an injury in his side (where Jesus was stabbed with a spear). Crane even describes the dying man as "a devotee of a mad religion" (9.37).
Jim’s final moment is absolutely horrific in its vulnerability, and the deliberate religious references seem to ask, "Where is God in all of this?" Because Crane abandons poetic grandeur in favor of stark realism, there is no resurrection for this Christ figure, nor is there anything noble or beautiful about his death. In this way, you can read the scene as an ironic twist on Jesus' crucifixion.
Or, you could not. Instead, you could argue that Jim really is a genuine (not ironic) Christ-figure whose painful death helps to "redeem" Henry. He sets the example for Henry, as if saying, "This is what it means to be a man." Watching Jim die is yet another trial and lesson learned for young Henry Fleming, who we know does eventually become a real man by the end of the novel.