Final answer:
Sigfried's invincibility stems from a magical event where he bathed in dragon's blood, leaving him impervious to weapons except for one unprotected spot. He also demonstrates strategic thinking in breaking enchantments, which complements his physical invincibility.
Step-by-step explanation:
Sigfried, a character from mythology, is invincible to weapons due to a magical incident during his creation. In the myth, Sigfried bathed in the blood of a dragon, which rendered his skin impervious to weapons. However, a single leaf fell on his back while he was bathing, leaving just one spot on his body unprotected.
Valorously approaching the brazen shield, according to the passage, he broke the enchantment, symbolizing that he overcame magical interference which often makes characters invincible. The skillful fighter quote suggests strategic thinking and positioning can make defeat nearly impossible, resonating with Sigfried's invincibility due to his strategic fighting abilities and the magical protection he has.