User blog comment:B214/General Discussion/@comment-29963364-20161223084324/@comment-10330822-20161228000801

Also, Jesus is implied to actually be the son of God, because the True Longinus killing him was  a big deal, but its possible in this work he didn't come back from the dead when he was killed. There is that theory that Jesus never came back and the disciples made up his resurrection. So, it kind of feeds into the true/fiction this series is flowing with when it comes to the faiths. Some parts of the religion are true, and there are some that are lies or just false.

Also, the Holy Relics are all tools that have something to do with Jesus, the Holy Grail is the cup he drank from at the Last Supper, the Incinerate Anthem is the essentially the cross he was killed on, and True Longinus is the spear that killed him.

My guess is that the reason all the weapons are so powerful is because they were connected to Jesus in one way or another, and his "power" fuels them. Even the True Longinus is "blessed with the blood of Christ". Not all the Longinus's have something sealed in them.