In Final Fantasy: Advent Children, Cloud and company have to face off against Kadaj's gang, a group of thugs with an undying allegiance to an entity they call their "mother." Kadaj's gang is reckless, arrogant, and willing to injure innocent children and bystanders in their bid for world domination. Despite being the 'bad guys,' they initially have some advantages over the Final Fantasy heroes. They're organized and they have great faith in what they do, as destructive and evil as they are. Cloud's group by comparison is scattered, having distanced themselves from each other, and what's more they lack a sense of identity and purpose. After the events of Final Fantasy 7 ended, they lost their common mission and ended up drifting about in the new Midgard. They don't know what they stand for or what's important to them, and that's why Kadaj's gang holds the upper hand for most of the movie.
But when Cloud and his friends start to communicate with each other and Cloud gains confidence in himself, they find faith in their campaign to save the world. Only once they have a faith that is stronger than Kadaj's can they begin to stand in his way. This story reminds me that faith is the fuel for anything of value that we do, and if we don't believe in a greater good behind what we do, we are unable to stand up to those who use their faith to inflict pain on others.