The First Image was a design for the grim reaper on the game over screens, but it began to progress to a more intergrated NPC character providing aid to the character should they be defeated in combat.
This Picture is a concept for a npc/ player controlled vehicle and overall assiting creature.
These final 2 Images are two forms of an enemy found in the main game, Hidden and revealed forms. In my opinion i think they still need some work because of a lack of proportion and detail.