Why is this the answer?

The answer is weapon because this clever riddle is like a secret code that asks you to find one special letter in each sentence. When you put all the letters together in the right order, they spell the word W E A P O N. This kind of puzzle is a very fun way to use words. Let us look at each of the six clues to find the six letters we need. The first clue tells you exactly where to look for the first letter: "My first is in wield, sever bones and marrow." The word "wield" is the best clue because the letter W is the very first letter in that word. The letter W is the first letter of our secret word. Next, we find the second letter in the second clue: "My second is in blade, forged in cold steel." We count the letters in the word "blade." The second letter is E. So now we have W and E. The third clue mentions a tool for shooting arrows: "My third is an arbalest, and also in arrows." An arbalest is an old kind of crossbow. The letter A is the third letter in "arbalest," and that is our third letter. Our word starts W E A. The fourth clue is short but strong: "My fourth is in power, plunged through a shield." If you count the letters in the word "plunged," the fourth letter is P. So far, we have W E A P. The last two clues finish the puzzle. The fifth clue says, "My fifth is in honor, and also in vows." The letter O is the fifth letter of "honor." Our word is nearly complete: W E A P O. Finally, the last clue is, "My last will put an end to it all." The letter N is the last letter in the word "end," which is a wonderful way to finish the riddle. When you bring W E A P O N together, it spells the word "weapon." A weapon is any tool used in fighting, hunting, or defending. The riddle used big, exciting words to make you think about knights and battles, but the real trick was simply finding the letters hidden inside those words.