It's fairly safe to assume that the abilities of Codex Chapter and Ultramarine Librarians will see a substantial amount of overlap.

Direct descendents might have the same powers. But even Crimson Fist Librarians (coming from a different gene pool) might have powers in common.

I think these are in general eligible for Codex Chapter Librarians: Word Of the Emperor, Glory Of the Emperor, War Cry, Inspiring Word.

Specific chapters might not use any of those but on average a codex-compliant chapter is likely to teach most or all of them. Which reduces the task of creating maybe just 2 or 3 new powers for a new chapter.

Any thoughts?

Alex

I could see a lot of overlap with sucessor chapters. Looking at the six chapters detailed in Deathwatch, they are all very distinct in character. None are simply minor varients of the others, so their abilities and powers are far less likely to overlap. But Ultramarines and "Generic Blue Marines" are likely to have pretty similar, codex-y powers.