It became more and more clear that supernatural forces were involved in the Second World War as it progressed. One of the more signs was what soldiers would call the Haunted. A soldier would claim to be able to see and talk to a the specter of a dead military man. Sometimes it was someone they knew personally. Other times the revenant was a historic figure, here to help our boys out.
Most of the Haunted would have gotten sent to a hospital for shell shock (at least) except for two things: they were completely rational aside from this quirk and they did have vital information they couldn't know by normal means.
Ghosts warned their tank commanders of minefields, and pointed out snipers to infantry. They indicated ambushes and traps and saved lives. On very rare occasions something appeared to others and briefly tore into enemy forces evening the odds at the least and destroying all opposition at best.
The Haunted is always a Tactician (OWB) or Leader (The Front). They have all the abilities of that class but are penalized 50% of their experience (they need half again as much XP or objectives to rise in level.) As they rise in level their unseen guardian becomes more powerful allowing the character to get more frequent and powerful supernatural effects. The levels and their favors are as follows:
1st Level Sixth Sense: The character may Detect Enemies three times a day. The effect lasts a minute. It only applies to living opponents. It won't tell you there's a minefield
2nd Level Warding: The character can detect traps three times a day. This will let them see inanimate traps such as mines, tripe wires and pitfalls. The effect only works line of sight but the character could see any hidden trap he could see otherwise.
3rd Level Omens: Once a day the character can ask their guardian a question about the future. The answer is usually enigmatic and often ominous.
4th Level Manifest: The spirit is now powerful enough to manifest once a week. This effect is powerful enough to cause any first level opponents to flee. Higher level opponents get a saving throw. Friendly characters never see the spirit in its true form but as something innocuous or a half seen shadow.
5th Level Materialize: Once a week the spirit can assume physical form. This effect lasts for 1d4 rounds. The spirit has Intelligence 16 and Wisdom 16 and in all other respects treated as identical to the human character. Though it looks and acts physical normal weapons have no effect on it. It can allow a character to roll with advantage by helping out or make attacks or even operate equipment. Other people seeing the spirit often mistake it for another soldier in their unit if not the Haunted himself.
Spirits have appeared on both sides and have occasionally fought. Two opposing spirits cancel out and provide no effects to their human charges. Additionally some artifacts have hurt or driven off the spirits and neutralized their benefits.