There are eight ghostly heroes.
The below five cannot be picked up (regardless of terrain);
- Clelia the Remembered
- Count Tollan
- Dorn Axegear
- Jen "Bloodfeet" Squishy
- Theobald the Titanic
The below three can be picked up;
- Bolgric "Meteor" Hamsides
- Emperor Uther
- Mahora the Resplendent
I noticed this in the final level of the Under Games, Meat Maker, where the player can find a neutral Theobald.
Customer support service by UserEcho