I'm not sure I like the idea of races surviving on mana and grace. IT already seems that waiting for mana and grace to go up is one of those things players already do, and increasing that waiting at all isn't going to make things very fun. I think fireborns using fire for food is good - it is relatively simple to do, and does change the nature of the race a bit. And it does then mean you don't need to carry food at all, as it doesn't do any good - you just need to carry those wands of fireball instead. Having a damage -> food mapping probably makes the most sense (the damage would be before modified by resistance). I sort of like the idea of a firepit in the tavern that the fireborns are hanging out in to get their food back up. Probably having free firepits in town is probably a fire exchange - if something like lava is used for the firepit, you don't get the food back that quickly, and even if free, it sort of makes up for the fact that there are probably many times when out adventuring there is no fire near by which means you need to use a wand/scroll/spell to feed. An extension of this idea might be that cold damage effective reduces food by some amount, but since they are already vulnerable to cold, that may be a bit much. For wraights, it is probably easier to abstract it to all races that are undead. I'm not sure the idea of sucking hp from those around you is that great - it would seem to make it more difficult for the wraith to adventure with others (as he would probably end up sucking his friends lifeforce also). Certainly tying it to the death of others works - things the wraith directly kills is easiest to do - things that die around the wraith (say by his friends actions) are harder, as when something dies, you then need to examine all the nearby squares to see if there is a wraith player around. The idea of a wraith carrying around a bag of live chickens for food comes to mind. To make it so that wraiths are completely hosed, they could also get some nominal food value from flesh items (maybe 1/10'th the value), and the basis there is still some small essence of life left in them.