From Halopedia, the Halo wiki
The Death Vow is a commitment made by a warrior where they consider their life to be sacrificed for their cause, even before they meet their end. In other words, they fully intend to spend their life fighting for the cause they serve, and are not fearful of laying down their life in its name. The Death Vow in particular is a Sangheili concept, though a warrior of any species could practice their own version of this vow.
During negotiations with Insurrectionists in 2526, First Blade Tel 'Szatulai of the Covenant's Silent Shadow believed that General Harper Garvin may have taken the Death Vow because of his fearlessness when forced to defuse a HAVOK tactical nuclear weapon with only seconds remaining before detonation. His discipline and dedication to the cause convinced 'Szatulai that he would need to watch Garvin more closely than the other Insurrectionists, as he may not be so easily fooled.
List of appearances
- Halo: Silent Storm (First mentioned)
- Halo: Silent Storm, chapter 18