Knowing that Sr. Ramon Salazar has no family, Lord Saddler must have used his strong faith in the Los Illuminados to his advantage to talk Sr. Salazar into undoing the seal of the Las Plagas once done by his ancestor.

Sr. Salazar would never do such a thing unless he was in some way being used unknowingly.
I should have sensed the Lord's dirty scheme sooner. I feel I'm partly responsible for all of this.

I have no idea as to what the Lord is planning, but Sr. Salazar was just being used.

It is too late now however, Sr. Salazar has already taken the Plaga into his body.