By default, a player can not attack or kill another player.
Each player gets a guardian angel when he (or she or it) is born,
and this angel will protect you from other players who try to attack
you. It will also stop you from attacking them.

There are, however, places in the world where players can kill each
other without interference from their guardian angels, or from the law.
One of these is the ancient place of duels, behind the village church.

A player can go to the Dark Temple - also behind the village church - and
abolish his guardian angel. This will allow him to attack other players,
who also have lost their guardian angels, but not those who still have
their angels.

Once you have lost your angel, you can never get it back.
