I'm curious about what factors go into determining how strong of an item will drop from a certain creature or chest. I've noticed that when returning to "lower level" areas I'm still getting drops from monsters that are level appropriate for the area, however drops from chests in the area seem to be of equal level to my character (not the area). I've also noticed that some boss monsters give you a unique item. Will this item always be the same thing any time it is killed, or do these items change in levels/stats based on some factor?
Additionally, are there any factors that change the chance of a better item dropping from a creature or chest? Such as a "normal" chest (the chest with the skull on the front) and the "horned" chest (Chests with the flat top and horns on the side) having different chances of dropping better items, or something to that effect?