When a person dies, their soul doesn't ascend to the afterlife automatically. The soul build's a connection with its body while alive, and remains attached to that body in death. Through natural decomposition, the soul gradually loses its connection to the mortal realm. At some point, when the body decays enough,the soul ascends to the next life where it will be judged by god. It will either be allowed into heaven or join the reincarnation cycle to be reborn and given another chance. The ascension of the soul however, is not guaranteed. While it is trapped in the body, it becomes susceptible to supernatural forces. There are invisible predators that prey on and consume vulnerable souls. These are called wraiths, which are angry spirits that have been unable to ascend properly and remain trapped on the mortal realm. These spirits are in constant pain, and seek to take out their agony and misery on the living by killing them. They are also given to consume other lost souls and grow in power. This has been common enough throughout history to be a real concern.
Priests are used to expedite the process of ascension. Through performing the necessary funeral rites and given a proper burial, they release the soul immediately and send it to be judged accordingly. These are rites only chosen priests can perform, which involve complex magical rituals that are learned through years of study. This has given the church a strong presence, and has made them a powerful force in humanity. Religion and faith play an important role in daily life of people, and priests are held in high regard in their community.
My question is about people whose bodies cannot be found: warriors who died in battle and can't be recovered easily, people who have been murdered and buried somewhere or have gone missing, etc. What is a good way to protect the souls of these people until they can be given a proper burial?