When your hitpoints go below the negative value of your constitution stat, you die. This results in you leaving your body and becoming a ghost. Ghosts do not have access to all of the commands that the living do, and they cannot carry items, be attacked, be followed by anyone, or join a group.
By attending Dr. Frankenstein's Lab in Eternal City, you can be reunited with your body. When you regenerate you will have lost 5% of your stats and skills, though they will never drop below the base level for your race. Other players may possess skills to assist your regeneration, and these skills may allow you to lose less than the full 5% of stats and skills caused by your death. Also, pigs may fly, and hell may freeze over.
No matter what method you use to regenerate, you will lose any experience points you were carrying at the time of your death.
When you die, the total amount of experience you lost as a result of your death will be displayed in the score command. Players who are large will gain a bonus to regaining their experience. This bonus will also be displayed in the score command.