El Gigante (literally "The Giant" in Spanish) is a towering B.O.W, created from humans that were exposed to Plaga parasites, and through an unknown method, grew to an immense size, acquiring great strength and brutality to compensate for their loss of higher reasoning.
El Gigante were created by Los Iluminados as one of their experiments on Plaga hosts. Due to their limited intelligence of feral nature, only a few were created, who were then imprisoned underground. In Autumn 2004, when Leon S. Kennedy ventured through Spain, one of them was deployed into the area behind the church to stop him. Trapping Leon in a small, fenced area, the creature was released from the mine it was incarcerated in. Unfortunately for his ganado handlers, he proved to be uncontrollable and succeeded in killing them all before turning to Leon.
A second gigante was deployed, again via the mines, to stop Leon and Ashley's escape; this creature was killed by Ada Wong, instead. Another two were encountered by Leon in the mines beneath the castle.