Those at swords' points

• The Bloods and the Crips, e.g
• Calhoun and Van Buren
• Pakistan and India, e.g.
• Opposing forces
• Some are public
• Montcalm and Wolfe, e.g.
• "A man cannot be too careful in the choice of his ___": Wilde
• Them
• Those opposed

Wiktionary Word definitions in Wiktionary
n. (enemy English)