Halo Alpha
Halo Alpha

Were you looking for the 105th Drop Jet Platoon?

They're in a whole different league.
— Crewman of 993-DD[citation needed]

The 105th Marine Expeditionary Unit (Special Operations Capable) is a UNSC Marine Corps Orbital Drop Shock Trooper (ODST) combat unit.[1] It is highly regarded as one of the best Marine units in the UNSC Defense Force.


Members of the 105th possessed 'exceptional' Esprit de Corps and immense pride and distinction within their unit, reflected by the customary comet-and-skull tattoo each received. Their motto, "Jump Feet First into Hell!", coupled with their employment of Human Entry Vehicles, earned them the nickname of "Helljumpers."

The 105th was infamous for its brutality, even toward fellow human troops. On one occasion, ODSTs from the 105th were involved in a fight with Spartan John-117, resulting in three ODST deaths and one severe injury.[2][3]


The 105th was around as early as 2525. Detachments of the Helljumpers have been stationed on a number of ships, including the UNSC Atlas. In 2552, subordinate (company- or platoon-level) units of the 105th were stationed on the UNSC Pillar of Autumn and fought in the Battle of Installation 04. This unit was the 22nd Tactical, which was instrumental in frustrating Covenant attempts to purge the Halo of humans. Unfortunately, any surving members of this unit were either killed when the Truth and Reconciliation was destroyed or when John-117 destroyed the Installation. Elements of the 7th Battalion were stationed on the UNSC In Amber Clad and participated in the Battle of Earth and on the Battle of Installation 05. A sub-unit of the 105th was stationed on UNSC Forward Unto Dawn, and participated in the Battle of Installation 00.

A squad from the 105th was sent on an assassination mission to take out an unknown Prophet, aided by a Cal-141.

Subordinate Units[]


  1. Halo Encyclopedia, Chapter 2, pages 56-57
  2. Halo: The Fall of Reach, pages 65-67
  3. Halo: The Flood, page ??

Related Pages[]