Following are a number of back-translations as well as a sample translation for translators of Isaiah 49:26:

• Kupsabiny: “I shall make those people who oppress you kill one another.
  They shall become drunk from spearing one another
  like one becomes drunk from wine.
  That is when all people shall know that
  I am God your savior,
  the God of power of Jacob.” (Source: Kupsabiny Back Translation)
• Newari: “those who make trouble and suffering for you, I will cause them to eat their own flesh.
  Like [they] get drunk from wine, [just so] they will get drunk from their own blood.
  Then all humankind will know this —
  that I, LORD am your savior,
  your redeemer, The Mighty one of Jacob.” (Source: Newari Back Translation)
• Hiligaynon: “I will- have those who oppress you (sing.) -eat their own body, and as-if they will-be-drunk by their own blood. Then all the people will-know that I am the LORD, your (sing.) Savior and the One-Who-Sets-Free, the Almighty God of Jacob.’” (Source: Hiligaynon Back Translation)
• English: “And I will cause your enemies to destroy themselves
  instead of murdering others.
  When that happens, everyone in the world will know that I, Yahweh, am the one who saves you,
  the one who rescues you from your enemies;
  everyone will know that I am the mighty God to whom you descendants of Jacob belong.’” (Source: Translation for Translators)