The nastiest
demon lord in
Nethack and Slash'EM, Demogorgon has
the power to make you deathly sick when he hits you. If you do not
have some means of curing yourself, you will die within a few rounds.
Fortunately, Demogorgon is quite rare in
vanilla Nethack; you may
well
ascend all classes without ever meeting him. In
Slash'EM, on
the other hand, he has his own level so you'd better be prepared for
him.
To survive your encounter with Demogorgon, you will need some way to
prevent or cure sickness. In vanilla Nethack, there is no
practical way to give your character sickness immunity, but in
Slash'Em, Necromancers and Undead Slayers are naturally immune to
sickness. In addition, Demogorgon cannot make you sick while you are
standing upon the mystic word Elbereth. The best way to cure
sickness is to cast the spell of cure sickness at 0% failure. If
you can't do this, you can use potions of extra healing, full
healing, or holy water (non-chaotic characters only). Using a
blessed unicorn horn is a bit risky, because if it fails you are
likely to die from your illness. See "getting out of trouble" for more methods of curing sickness.
It's safest to kill Demogorgon without giving him a chance to
retaliate. Because he is a demon, he is immune to death rays,
but he can still be petrified or disintegrated like almost any
other monster. Alternatively, wear a ring of free action, wield a
potion of paralysis and hit him with it, then lay into him with your
weapon. You may need to repeat this with another potion of paralysis
to ensure that he remains paralysed until he dies. If you are a
Drow, your attacks will put Demogorgon to sleep, but it is
impossible to put him to sleep in any other way.
Engaging Demogorgon in honourable combat is not recommended, as far
too many candidates for ascension have fallen victim to him. If you
must do this, make sure you are very fast and unburdened and
wearing an amulet of life saving. Use the upstairs/downstairs
trick to stop him teleporting away to heal himself.