Devlin Stone's coalition was a military alliance formed under Stone's command. It was the biggest coalition and military force never formed. It was The Alliance was focused in defeating the Word of Blake, liberating any planet occuped by them and puting an end to the Jihad. After liberating any other planet under Blakist occupation, the war ended with Operation SCOUR, the liberation of Terra.
Devlin Stone, after the end of the war, managed to convince all the Coalition leaders to leave him form his own state, the Republic of the Sphere, and disarm themselves, or at least reduce much his armies. This was the beginning of a two generations peace era who ended with the Blackout.