A mortal is a human being that has failed to achieve godhood.
The Origin of Mortals
Six days after "The Beginning" God, the snake, the angel with the fiery sword, and a couple of unicorns all needed some entertainment. So, God created the first mortal- Adam. Predictably, Adam wasn't living up to God's expectations. God put Adam into a deep sleep, and stole a membrane from Adam which he used to create mitochondrial Eve. Adam and Eve were immortal until they were tricked by the snake that God created into stealing God's "forbidden fruit". The "forbidden tree" is where God kept all his commandments, dirty laundry, and recipes for last suppers. Aside from that, it was also the first ITree and produced some damn good IPods. God punished them by inflicting upon them original sin. Adam didn't understand the ramifications of this until 930 years later when he died of syphilis. Fig leaves became the first fashion statement as all mortals now understood they were naked. God commanded that Adam put down that sheep, and get busy with Eve, because all mortals would be descended from them. God decreed that any mortal who has eaten ambrosia will become immortal, and thus a god. The first to take advantage of this was the talking snake- Lucifer.
Mortals were having a good time of it until about the year zero, when John the Baptist suspected something was a miss. Down at the river he was having his annual bath when this guy named Jesus wanted to be baptized. Jesus smelled great, didn't sweat, and kept referring to himself in the third person. John realized he was in the presence of an immortal. Jesus thanked John for the baptism, but then forgot to warn him about that dancing bitch Salome. This was typical mortal to immortal interaction, you do something like save their soul for all eternity, and they forget to warn you about this chick whose Dad is a real hard ass, and that will cut your fucking head off for watching his daughter get freaky on the dance floor. Jesus made the rounds of the pre-war torn middle east, and people were getting a little tired of this immortal guy, who didn't even hand out any ambrosia for the rest of us. Herod- the local sheriff at the time had Jesus arrested, and after a popular vote, and disputed recount, he was sentenced to die by crucifixion. A couple of mortals were also sentenced to be crucified, and hanging on their crosses on either side of Jesus asked him what was up-
Good Thief: "Hey since your up here with us, do you think you can get us out of this??!"
Jesus: "You mean make you immortal?"
Bad Thief: "Duh!"
Jesus: "Um, yeah, I can't do that, but what I can do is let you go to heaven, even though you're kind of being a dick to me right now..."
Good Thief: "Heaven? I don't want to go to Heaven and be one of your pets, I want to live!"
Bad Thief: "Yeah, live stupid! I've got forty horse flies on my left nipple, c'mon 'Son of God' let's see you will us off these crosses!"
Jesus: "Alright! I wasn't going to go through with this, but I guess I'm going to now. I will die up here with you two guys..."
Fluctuating from mortal to immortal status for three days, Jesus succeeded in fooling the thieves and returning from the dead, a feat most immortals won't even try.
Mortality in the 20th Century
The twentieth century exceeded all other centuries before it with a million and one different ways to die. Mortality was a hot button issue, with the rich trying hard to find ways to cheat death. Popular methods included- cryogenics, pills, inventing holidays, mummification, and wearing magic underwear (see Mormons).