In Nioh, the samurai hero will use amrita to level up and increase his stats. Each stat is the main representation of a certain skill. For example, strength is used in axe, and dexterity in dual wielding. When the samurai’s stats are improved, his skills in these respective weapons etc will improve. The hero samurai warrior must use the amrita at the shrine to level up. Once a certain threshold is reached, the samurai warrior needs to level up asap using amrita to become more powerful.
The unwise samurai warrior will continue fighting on and on with an excessive amount of amrita. However, at a certain stage, the warrior will no doubt perish in the perilous world of Nioh. Then the samurai warrior will have to get his amrita back again from his grave. No easy feat, as tiredness and frustration will no doubt result in a double demise. In this case, the amirata will be lost forever.