Captain Bluntschli is a thirty-four-year-old realist who sees through the absurd romanticism of war. Furthermore, unlike the aristocratic volunteers who are untrained, amateurish idealists, Captain Bluntschli is a professional soldier, trained in waging a war in a highly efficient, businesslike manner. These methods allow Sergius to refer to his ability to wage a war as being low-class commercialism, devoid of any honor and nobility. Bluntschli would agree with this appraisal since he sees nothing romantic about the violent and senseless slaughter of human beings, even though it is his profession.
Being a professional soldier, he adopts a practical and wise view (his name is a combination of Blunt, plus the ending, which in Swiss means "sweet" or "endearing" or "lovable"). Given the choice of being killed or saving his life by climbing up a balcony and into a lady's bedroom, he chooses unheroically not to be killed. Practically, he knows that a dead professional soldier is of no value to anyone; thus, he saves his life by the most expedient method available — he hides in a lady's bedchamber. Likewise, given the choice of killing someone or of not going hungry, he chooses to eat rather than to kill; thus, he carries chocolates rather than cartridges, a highly unromantic but very practical thing to do.
When Bluntschli first hears of Sergius' cavalry charge and refuses to view Sergius' actions in any way except as a foolhardy display of false heroics, he reveals his complete practicality and subjects himself to Raina's charge that he is "incapable of appreciating honor and courage." Yet, his questioning of Sergius' actions causes Raina to question Sergius' qualities.
Bluntschli does possess some qualities which cause Raina to exchange the "noble and heroic" Sergius in favor of him. Raina's perfect honesty, in fact, allows her to relax and to come down from her pedestal. Bluntschli's fondness for chocolates in the midst of war is appealingly incongruous. His docility, combined with his efficiency, endears him to others, especially the entire Petkoff family, and, finally, he reveals to the established group that he is an incurable romantic. He explains that he could have sent the old coat back, but that he wanted to return it personally so that he could have one more glimpse of the entrancing Raina. Thus, he wins her for his "affianced wife."