Well this is my chapter for a comp.

History
The acid warriros are a very young chapter, founded during the 13th black crusade on Kasr Holn alongside one of the 3 companies of the Subjudicators chapter. It is not known which chapter these warriors hail from. It is speculated that these warriros were created by the primarch of the salamanders Xavier. Possibly to spare the lives of his won warriors, maybe even to pass on the legacy of his chapter in dire need.

Combat Actions
The founder and primarch of the chapter, Commander Akeris (known as innervision) because of his mystical powers embarked upon the eye of terror with great haste. The subjudicators and remnents of the Space Wolves, White Scars and Mortificators held the areas speaking of 3 great ships bombarding the forces of Chaos before Massacring the tide embarking upon the striken Imperial forces.

Shortly after, Commander Akeris and his warriors left, turning up on the planet of Solar Maritius where these brave warriros have boltstered the Imperial lines where to this day they remain, sending seige after seige hurtling back in which in came in disarray.

Organisation
The acid warriors are organised into Adeptus Astartes based upon their task. It is quite common for entire tank based companies to sally forth from the ramps of the Acid warriors thunderhawks, but in some cases, Hordes of marines will march to battle in perfect formation.

Homeworld

The Acid Warriros have no specific homeworld. It is speculated they spend time upon the crone worlds inside the eye, but there is no way to prove this.