FIXED - No longer crashes when hovering/placing artillery after a martyr has stolen one of your pieces.
CHANGED - Clarified necromancer inspector description
It has taken me all morning to figure out why hovering your artillery in very specific and unknown circumstances would cause a crash, so I'm going to explain what was happening because it feels like a waste not to share it.
I eventually traced it back to martyrs. When an enemy martyr takes a piece, it's supposed to delete itself. But it was accidentally adding itself back to the list of played pieces again (clashing with the 'place from shop' code), but it would get added to the "placed on board" list of pieces without actually standing on any tile.
So when you would hover your artillery specifically, it would look at all the enemy pieces it could attack that have been played, (as opposed to looking at the immediately adjacent pieces like other pieces do). But that enemy martyr would still be on the list. The artillery would request which tile the martyr was standing on, but it was deleted so it wasn't standing on a tile. So "no tile" would be added to the list of tiles the artillery could attack, which causes a crash downstream.
As for the description of the necromancer, it was written from the assumption that the necromancer was yours. So when you hovered an enemy necromancer, it made it sound like it revived your pieces, not theirs.