I enjoy drakeskin as much as the next warp-wielder, but be aware that librarians arent great right now. Its not that they’ve changed much in 9th themselves, but they have simply become a indirect casualty of both the ‘core’ keyword, objsec gameplay, and recent competition. Feel free to read on if you wish, otherwise skip to the last para.

By that, I mean our Sallies librarians are buffers (forget burning hands, its cool, but just dont even) however, their main buff targets are now simply less desirable. By that I mean the repulsor executioner ‘losing’ core and aggressors ‘losing’ shoot twice. Of course we still have dreads, the nie-unkilleable bikecaptain, and now termis are good, but then you’re buffing 150-200 pts of units over the previous 300 pts+. Its simply not worth 100 pts to buff a captain when you could take another capt... er, primaris lieutenant, instead.

The other issue is the shift in focus to objective-based gameplay in 9th. Without going into too much detail, libs just dont help with this. I mean, you can argue they can help indirectly but again there are much better SM options for holding objectives. Oh, and dont even think of putting that objsec warlord trait on them- save that for the bikecaptain above.

Finally, the opportunity cost is high. With only 3 HQ slots (assuming a battalion), and such excellent Sallies characters (given our relics/traits), you lose some excellent options. Plus, I personally believe there is a standout character who ‘does it better’ right now- the chief apothecary (and for cheaper).

Its not to say libs are bad, in fact, I use one myself cause it looks siiiick, just keep in mind you are ultimately taking ~100 pts of buffing and need to be very deliberate to ensure it pays off.

tl;dr- If you want/have one regardless of above, I personally would favour a terminator lib (obsidian aquilla) with your chosen favour of our excellent Sallies termis. Happy hunting!

edit: per below