Diego, 18, is Father Clifford's assistant. He came to Rivet City a few years ago with his father but was abandoned. Father Clifford took Diego in, and the two have become like father and son. Diego assists Father Clifford with his church work and wants to be a priest when he gets older. He has strong feelings for Angela Staley and spends much of his free time with her. However, he is also a devoted Catholic. Because she is only 16, he does everything he can to keep his feelings secret, although Angela sees right through him.
A Nice Day for a Right Wedding: There are rumors of his involvement with Angela Staley. The player can either force him to relinquish the church or the girl (by saying you will tell the father, or telling the father directly). If you convince him to choose the girl they will end up getting married and you have the option to attend the ceremony. You can also give Angela Staley some ant queen pheromones which will make her irresistible to Diego. Diego will then leave priesthood to marry Angela.
Diego may also unofficially start the Church Donations quest. If asked about donating to the church, he will tell you to give your donations to Father Clifford .
If you choose to give Angela Staley the ant queen pheromones and then speak to Diego before the wedding he will state that Angela is not an honorable woman, but he also claims he is intended to make her an honorable woman. Despite this, there are no changes in Angela's behavior after the wedding.