CLAUDE FROLLO

Claude Frollo raised Quasimodo as his penance for killing Quasi's mother. He was ordered to do this by a man of power in the church, this is a character who obeys the church, and believes in the word of God. These ideas are noted in the work of N. James.
Frollo is distraught when he finds himself lusting over Esmeralda and sings about it in the song "Hellfire", which you can view below!(Video not my own, owner found here).
Notice the symbols of hell that are in the scenes when Frollo sings "Hellfire"(eg. the red hooded demons, shapes burning in the fire etc.). In my opinion it's a very obvious depiction that sins, such as lust will send you to hell.
Although religious, Frollo is not a "good guy". It's interesting to me that Disney let someone so outright religious be a villain. He even refers to himself as better than non-religious folk in the song "Hellfire". If you're interested in more on this check out this video!
The theme of eternal damnation surrounds Frollo like a dark cloud, as explored by G.M Sully. Damned to raising Quasimodo as penance, damning Esmeralda to the fiery stake, and in the end he falls into a fiery pit (a clear representation of hell) to be eternally damned there.
Frollo's character brings a lot of darkness to this film (there are even stories of parents leaving the theater because they thought his character was so inappropriate.) Why did Disney do this? Check out the "Why Religion?" tab for my thoughts!

Bonus Points on Frollo& "Hellfire":

Frollo's villainous character was originally written to be an Archdeacon in Hugo's original publishing.
If you know any Latin or very traditional Catholic prayers you might pick up that in "Hellfire" it starts out with a prayer from Roman Catholic mass, and when Frollo sings that it's not his fault that he lusts for Esmeralda it seems to me that the demons chant back "me culpa" which thanks to Google Translate I found out means "blame me". So the demons are basically admitting fault for Frollo's sin.