Eden is the Biblical Garden that served as the first home of Adam and Eve. It is the first and largest level of Dwarf Hammer, designated Level 0; the vast majority of players never survive long enough to stumble upon the entrance to the Caverns of Creation, and that's not even taking into account the possibility of Zero-Move Deaths.
Though the hostile creatures of Eden are all flesh monsters (though there is a 1 in 99 chance that the game will spawn a single Crystal Germ), making them highly susceptible to spells (particularly Horrible Burning) and melee attacks, their unusually high HP (though not by Dwarf Hammer standards) makes them quite formidable. Beyond that, creatures on the Eden level have a 4 in 5 chance of being born in the Year of the Ram (which of course yields a +20 unblockable hit point attack bonus). Because starting level adventurers never have more than 3 hit points, sustaining a single hit from most enemies on this stage will result in death.