At first, Macil seems to be that type of guy who fights for justice and freedom. First, you have to complete a few missions for him (such as freeing the prisoners). After that, his forces are ready for an assault on the castle and he'll tell you to join the assault and destroy the Programmer. Once the Programmer is dead and The Front has taken control of the castle, Macil will tell you to find the other sigil pieces, and to seek the Oracle. Later, the Oracle will reveal Macil's true interests by saying that he is the one who holds the "third piece". Spoilers end here.