The Librarium of the 10th Host is made up of FIVE distinct groups of Librarians and sorcerers.

Old guard:

These three are survivors from the old days, each an Astartes sorcerer of some potency. They are not, however, much use as librarians. Their talents run towards battle and general chaos-making. Consequently their usual role is to support companies going into battle, especially if enemy psykers are present.

Huacas - Veteran of the long war, his sorcerous potential was unlocked very early. Not an Astartes of many talents, but he has a knack for summoning unholy fire, a lot of fire. A highly skilled combat sorcerer, protects his brothers from fire/metals and summons burning metal and or warp fire.

Mannan - Sees strands of men`s faith/ can also predict out comes of battles with some success. Popular with the captains of the host as a soothsayer, can help change outcome of battles by predicting enemy's movements/actions.

Thanatos - One of the most experienced sorcerer in the 10th. Not as old as Huacas but far more diverse in his skills. Excels at counter magic, He more than any protect the warriors in the host from hostile psykers/sorcerers. Limited offensive capabilities.

New breed:

From the same gene-batch four psykers have risen and re-opened the Librarium of the 10th Host. The power of the gene-seed that Castor made his first Astartes with, manifests again.

Fierelus - Learns from the other psykers in the host, be they Astartes, sorcerer or rogue psyker. Fierelus believes that the path to power takes many forms.

Hanno - Has opened the old codixes of the host to learn the secrets of long dead masters, believing that the path to true power lies in the hallowed past.

Baalhaan - Sits in council with the whispers from the warp, believing that his rise lies with the gods' good graces.

Malchus - The most powerful of them all, combines the ideas of the others. Of them all he shows the most promise.

Lumin's get:

Lumin's people include whatever astropaths you've corrupted, plus those psykers and sorcerers that focus on fortune-telling and communication. Their job isn't very flashy or heroic, but it is important for the Host.

Lumin - Your Astropath-sorcerer.

Emona - His female feral-world apprentice (the one with the cybernetic eyes and facial scarring)

Witches and warlocks -

Nissimon's coven:

Nissimon - Master Chaos sorcerer.

Apprentice sorcerers - Nissimon has taken only a couple of apprentices. They do his errands and asssit him during rituals, but are rarely allowed to do anything on their own.

Nouri's cabal:

Norui - Sorcerer of Tzeentch.

Thrall-Wizards of the Cabal - His twenty or so slaves, each a psyker/sorcerer.