This denomination of Thrall is the same in both Vampire: The Masquerade and Vampire: The Requiem. A thrall is usually a mortal, and may have their service reinforced through the use of Disciplines such as Dominate or Presence/Majesty.
Mortal thralls may become retainers or even ghouls if they prove exceptionally useful. Inversely, those with little to offer their master or mistress may simply serve as part of the vampire's herd. In VtR, thralls are somewhat less reliable than their VtM counterparts, since many will come to suffer from the effects of blood addiction.
Vampires with the misfortune to become thrall to another vampire are typically young, with relatively weaker blood (expressed via generation or Blood Potency, as the case may be). Vampires who are bound as thralls to elders or even Methuselahs are more common in VtM than in VtR, since VtR vampires risk losing the power of the blood during torpor through the effects of the Fog of Eternity. Supernatural beings other than vampires rarely become thralls, although it is theoretically possible for any being that can be subject to the blood bond to be forced into thralldom.