After Speaking with Basirah:

El Musica, La Simpatico and El Puno sit in contemplation on what to do once the demons arrive. However they can wait no longer as they are here. Two demons, clad in black clothes and stetsons show up. Twins. A brother and a sister respectfully. Why they show up now rather than when is because they wanted to see what the Trio was capable of. They make their move. Not by stepping in themselves, but possessing two locals. The first, a mother of two children, just suddenly grabs a knife and tries to attack El Musica. The other locals pull their guns out, but El Puno takes out his shotgun warning them to get back. Knowing she's possessed El Musica and La Sapito restrain the woman, but a man they possess attacks them from behind prompting the bartender to shoot him, before begging God for forgiveness. What follows is a tense exorcism, not just to drive the demon out, but to interrogate her for information. The demon refuses before El Musica pulls out a smaller gun. She recognizes it right away as a squirt gun and laughs at his attempts to scare her. El Musica smiles and says "Not just any water. Holy Water." He squirts her causing her to reel in pain, while El Puno prays. After a series of squirts and demands, she relents, letting them know that they're the last line of defence before the Cowboys of The Damned prepare to unleash an Outer God. Instead of simply leaving, she kills herself with the knife. Striking a huge blow to the Trio as they couldn't save her. The locals have had enough and demand the Trio to leave. Which they make preparations to.

I didn't want the whole story to be too easy for our heroes. Plus I figured for demonic possession, a lot of movies involving them often have heavy downers so. When in Rome.