Editing Chapter Sigma (section)

===Chapter Combat Doctrine=== 
[[File:Chaptersigmamarine.jpg|thumb|right|200px|Chapter Sigma Marine]]
The Chapter Sigma closely follow the guidelines of the Codex Mathematika during combat operations, which assigns value to all facets of combat, including damage to enemies, harm to self and collateral damage. Each Space Marine has been extensively trained to maximise the sigma value of these combat calculations, to achieve the greatest possible effect with the least effort.

This has led to backlash against their tactics when they allow enemies to retreat because the cost of total annihilation was too great, or when they let civilians die in order to assassinate an important target.

The chapter has a great amount of flexibility, with captains serving as the first of equals, and the chapter master considered as the first of firsts. Ordinary marines are encouraged to counteract their commanders if they have judged them to have made a miscalculation, due to the flexible and subjective nature of the Codex Mathematika.

Apparently due to a quirk in their geneseed, many psychically-gifted aspirants either perish during the implantation procedure or see their gifts diminished to the point of uselessness. As such, librarians are highly valued amongst the Chapter Sigma, totalling between 2 to 5 usually. As such, the chapters librarians are highly prized and tend to serve support roles, far away from the heat of combat. The value placed on the librarians is extremely high, with entire companies willing to sacrifice themselves for a single librarian. Due to those dangers, the chapter rarely confronts the forces of chaos which would threaten their librarians, except in the case of the accursed Sa'loxir'ath.