Winning and Scoring
A Battle is over when either there is only one Warlock left standing, or when there isn't even one Warlock left standing. (Surrendered Warlocks go and sit down.)
If there isn't a winner of a Battle (ie. All Warlocks are either dead or surrendered simultaneously), nobody gains any points; all who died lose all their points, all who surrendered lose one point. There's no prestige in a draw. The exception to this is if, in the final round, one remaining Warlock surrenders and all other remaining Warlocks die - in that case, the surviving, would-be-surrendering Warlock wins. After all, who's to know you surrendered to a corpse?
If there is a winner, they score one point for each opposing Warlock in the Battle. Surrendered Warlocks each lose one point, if they have one. Dead Warlocks lose all their points, so it's worth surrendering before you die.
None of these Score changes occur for a Friendly Challenge, though the Won/Played/Died counts of the Warlocks are still updated. For a Very Friendly Challenge, even the Won/Played/Died statistics go untouched.
You can only compete in Ladder games against people with a similar score - within 5 points of your score. A table of Players and their scores can be found here.
If, by the end of a game, your score is 5 points greater than the average score (rounded down) of the two players when a duel began, you do not gain a point from the win - this is to prevent players abusing the scoring system by starting many games against new, weak players when their score is in range, and thus attaining a high rank without ever having to play an experienced player.
The Players list is ranked primarily by score. Players with the same score are placed in order by how many times they've died as compared to the number of games they've played. Players for whom both of those are the same are ranked by how many times they've won as compared to the number of games they've played. If all three are the same, the order is arbitrary.
There is also an Elo-ranking system, whose technical details can be found here.
Next: Code of Conduct