Lesser daemon of the Liberator: Unchained
Greater daemon of the Liberator: Chainbreaker
Daemon familiar of the Liberator: Cainite Companion
All three obviously heavily feature the motif of shattered chains/slave collars. It is said that their glowing eyes are a reflection of the Fire of Liberation, the indomitable human spirit's yearning for freedom.
Any locked door that leads them toward the enslaved and unjustly imprisoned will open for them.
All three abhor the notion of being bound in any way. It is virtually impossible to trap them/bind them to an object or imprison them in a daemon engine.
Cainite daemons know the true nature of a human with a single look. They refuse to parlay with those that would walk over corpses to further their own gains. Mercy can be offered, but only for a honest attempt at repentance.
They do not attempt to possess vulnerable psykers, in fact they often clash with other daemons to protect humans that are vulnerable to possession.
It is possible to make a pact with them, requiring the pact maker to make an offering. Such offerings generally center around oaths to further the cause of Humanity's Liberation, though gifts of amasec made by one's own hands are also accepted.
Cainite daemons prefer to avoid direct confrontation, yet if forced to fight they are incredibly skilled combatants, both as individuals and in groups. Daemons and followers of Nurgle are the singular exception, as Cainite daemons will go out of their way to fight the forces of the plague father.