The Gargoyles are a bloodline created by the Tremere as servitors. Although technically not a Tremere bloodline, the bloodline is largely under their control.
The Gargoyles were created using the blood of three different clans: the Gangrel, the Nosferatu, and the Tzimisce. The blood was combined to form three specific types of Gargoyle: scouts (Gangrel-Nosferatu), warriors (Gangrel-Tzimisce), and sentinels (Nosferatu-Tzimisce). Warriors focus on Potence and combat Abilities; sentinels focus on Fortitude, Alertness and other such Traits; and scouts practise Stealth, Survival and the like.
The bloodline was first created via Thaumaturgical ritual in 1167, created in three variants: the Gangrel-Nosferatu, Gangrel-Tzimisce, and Nosferatu-Tzimisce. For the first several centuries after their creation, all their "powers" were in the form of rituals cast upon them by their Tremere masters.
At this point in their history, Gargoyles have "evolved" beyond the need for Tremere rituals, instead having developed their own special Discipline, called Visceratika.
Many free Gargoyles during the Final Nights have discovered that while they may be vampires, they are also practically their own species. Some even claim that they are capable of biological reproduction with other Gargoyles.