Stage One: Stage one when active shuts off the users Pain receptors, meaning they can't feel pain, increases their chakra amount a little bit (+500), grants a higher amount of Chakra control (+15%) and the user can 'feel' around them, though how large the radius they can 'feel' around them is dependent on how much they train with it.
Stage one is unlocked by experience exetreme happiness and excitement (almost euphoric)
Stage Two: Stage 2 when active does the same as Stage one, but their chakra amount increases much more (+2000), chakra control is increased more (+17%), and grants the user the ability to see into the future when a pulse of chakra (-100) is sent to their eyes. How far they can see into the future is dependent on how much they train with it. First time users can only see .5 seconds into the future.
Stage two is unlocked by experiencing great anger and rage (almost beserker-like which is exetremely hard to accomplish)
Stage Three: Stage 3 when active does the same as stage 1 and 2 but their chakra amount increases by an even greater amount (+5000), chakra control is increased a little more (+19%), and the user can change their Chakra Nature/Element using Chakra (-4000). Changing Chakra Nature/Element is not permanent, it's only changed to that nature when it's activated. when it's turned off the users chakra nature/element returns back to their original element/nature.
Stage three is unlocked by experiencing great pain and sadness (almost suicidal)
Final Stage: The Final Stage when active does the same as the previous stages, but their chakra amount increases even more (+10,000), chakra control is increase a little more (+20%), and the user can Summon and Fuse with 'Demons' from the Demon Summoning Realm. Fusing with a demon costs excessively large amounts of chakra (-30,000) and even more to maintain it (-25,000 per round when fused). The effects and skills of fusing depends on the Demon (player) and the effects revert and the demon unfuses and desummons once it is deactivated. The user CANNOT summon any of the Bijuu though, and they still follow the Summoning Chakra Costs. Fusing also presents a large danger with the Demon taking over their body if they don't have enough will.
The Final Stage is unlocked by dying once. Once the user dies they will be sent to hell to 'negotiate' with the king of demons there. If the deal is accepted by the king than the user is revived and has access to the final stage. If not then the user dies (If they are part of a village they will wake up in the hospital but they won't be able to access the final stage or negotiate with the king of demons for the rest of their life.)