Sins of the Prophets
From Halopedia, the Halo wiki
Sins of the Prophets (SotP) is a fan-made total conversion mod created for the 4X real-time strategy game Sins of a Solar Empire, most prominently its Rebellion expansion. Developed by Chokepoint Games, SotP combines space battles that involve dozens if not hundreds of ships with the fast-paced action seen in the official games. Set during the late Human-Covenant War, players are able to play as either the UNSC or the Covenant, with an asymmetrical balance to ensure that neither faction plays the same way.
SotP was originally founded at some point in 2008. They released their first beta for the Entrenchment expansion on Jan 17th, 2013, which consisted of only the UNSC faction. On July 22, 2014, they released a second beta ported over to the newer Rebellion expansion, which added the Covenant Empire as a playable faction.
In December 28, 2019, Slugfest Studios announced that it had merged with two other modding teams - Broken Line Studios and 363 Productions - to create Chokepoint Games. This decision was made because all three teams were sharing resources and personnel, as well as to avoid potential legal issues. They also announced the development of a new mod for Arma 3, which was later revealed to be Far Isle.