When EVOKED, it becomes a living exo-skeleton designed to take abuses then disappear. I have a similar spell concept posted but for a more advanced and permanent idea of armor. This is more something that is lower level of power for the defensive capacity but can be cast on other players for limited effects, even possibly the first Empath Massie! I really like the concept to add greater variety for mass spells--#1, it's good for RP, all the people do more interacting in a positive way if they are doing massies and it usually makes the adventurers appreciative. No matter how often they are cast, there's always new players needing them who come in and out of the TSC area. In fact,I have an idea for high level characters to use a special utility to get all main nodes in a city together in a special realm just for massies-- 'Remote Massies' if you will. This is a sparsely populated place all combined so a way to link up the TSC's of Elanthia just for the purposes of sharing spell benefits is probably worth taking a look at.

Anyway, Bone Shatter creates a living exo-skeleton on the outside of the armor you wear! The effects for the Empath will start with a Level 1 Crit 'shatter point' then move way up from there with Lore and skill level. For adventurers who receive the spell from a friendly Empath EVOKING it on them, they will be able to get a max of 1 Level/Minor crit shatter point. This will lover the impact of a critical, so it will act like critical padding that goes away on impact. Also it will be awesome to see the spell designed to fall apart in ways that make sense, more macabre like if the neck goes, the head goes too. If the abdomen goes, you lose the extremeties!

This will be a good chance to design the spell a little bit differently than usual for this world! How about a level based 'hardness' so that the crit wound might not go up, but just raw experience will increase the number of shots the exo-skeleton can survive or the overall damage. Perhaps the Empath may select damage or critical protection by a certain kind of Focusing or Attunement. Perhaps the highest skill levels get the skeleton to start swiping at the enemy a little bit, deflecting a blow and maybe taking a swing (and possibly crushing themselves on the enemy) for little tiny added damage, stuns, etc. but I would think only at the highest levels for the spell. The 'hardness' would be the shatter point so the 100th level Empath whose three times the level of experience of 100 and still gets boosts for each level will have dozens of strikes possibly to get the thing to shatter but the path who just gets the spell will most likely see a weak blow crush the area it made contact with.

If it's a Mass Spell effect I would think a single cast for 20 minutes plus 1 minute per level of training. Everyone gets a spiritual exo-skeleton that looks, sounds and protects like real living bones. When it's lost the bones wind up evaporating into a white mist as they were only there manifesting from the spirit world.