R'ea'kuk-pattern command shuttle
From Halopedia, the Halo wiki
The R'ea'kuk displays many outward similarities to the Spirit family of troop carriers; in particular the Dextro Xur-pattern. It shares a number of features with the Dextro Xur such as the twin pronged hulls, though is equipped with additional capital ship-scale proselytization network relays and defensive augur arrays.
Befitting its name, the command shuttle served in a role comparable to the larger transport shuttles employed by the United Nations Space Command (UNSC) or various human megacorporations, working to ferry high-value Covenant military officers or political figures (such as Hierarchs, Minor Prophets, Ministers, San'Shyuum and Sangheili High Councilors etc) on their deployments outside of High Charity. In this role, they had many features such as capital scale proselytization network relays and specialty defensive augur arrays.
Due to this usage, the R'ea'kuk was rarely deployed on the front lines during the Human-Covenant War, and the rare occasions in which it did make contact with human forces saw the UNSC devote considerable effort to target analysis and tracking of the individual shuttles encountered.
The command shuttle is one of many vehicles cut during the production of Halo 2. In the original storyboards, the command shuttle had a very different visual look, and was intended to be used to deploy the Arbiter and his Special Operations Sangheili during the level The Arbiter. It was later to be used at the end of deltatemple as the personal transport of the Prophet of Regret, before finally being seen in the final epilogue cutscenes.
The model for the command shuttle was unearthed by the Digsite project, and officially canonised in an issue of Canon Fodder The dropship reuses the textures of the original Halo: Combat Evolved Spirit in a similar fashion to the Brhi Xur-pattern Leech boarding craft, though was developed extremely early during the development cycle of Halo 2 - during the era in which the game was still mostly the Combat Evolved engine.