The 26th Founding of Space Marine Chapters occurred in 738.M41. There is only one known Chapter that was Founded at this time -- the Mentors.

Little is known about the Mentors in Imperial records, though the Mentors are known to be a reclusive and suspicious Chapter of Astartes who no longer trust other Space Marine Chapters or the Imperial government, preferring to work alone and unobserved by all save the foes of Mankind and the Emperor Himself.

They are the second Chapter of Astartes to be designated number 888 (the first being the now-lost Star Scorpions). This came about because the Star Scorpions, a Chapter created during the 25th Founding, suffered from both a high rate of mutation within its gene-seed and had the terrible misfortune of becoming lost in the Warp after coming under attack from powerful daemonic entities.

While stocks of the Star Scorpions' gene-seed survived the loss of the Chapter, the high rate of mutation found within it made it useless when the Adeptus Mechanicus moved to try to reconstitute the Chapter and eventually the Magos Biologis and chem-architects were forced to concede defeat. For a time it seemed that the Chapter numbered 888 would never be raised again, but some years later, with a new Founding in the offing, the Mechanicus was persuaded to revisit the Chapter regalia.

Thus, during the 26th Founding, the Mentors Chapter was born. They received the colours and number of the extinct Chapter but instead of the redundant gene-seed, they were given an entirely new generation of genetic material collected from the storage banks of Terra's gene-laboratories.

Select 26th Founding Chapters

Successors of
Mentors Unknown Unknown Classified Often referred to as the Mentor Legion in Imperial records, the Mentors are a 26th Founding Chapter created in 738.M41 and are the second Chapter of Astartes to be designated number 888 (the first being the now-lost Star Scorpions).


  • Codex: Armageddon (3rd Edition), pg. 18
  • Codex: Space Marines (6th Edition), pg. 73
  • Codex: Space Marines (5th Edition), pg. 29
  • Imperial Armour Volume Two Space Marines and Forces of the Inquisition, pp. 74, 181
  • Insignium Astartes: The Uniforms and Regalia of the Space Marines
  • White Dwarf 249 (UK), "Index Astartes - Emperor's Shield"
  • White Dwarf 98 (UK), "Index Astartes-The Mentor Legion" by Bryan Ansell, Alan Merrett & Paul Cockburn, pp. 39-44
  • Spear of the Emperor (Novel) by Aaron Dembski-Bowden, Ch. 20
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