Challenge rating

From NWNWiki

The higher the challenge rating (CR) number, the more powerful the enemy. Commonly four characters of a certain level are able to defeat one creature with a CR equal to the average level of the characters with a moderate amount of difficulty.

It can be viewed by examining the creature.

• Impossible (purple): 5 or more levels higher
• Overpowering (red): 3 or 4 levels higher
• Very Difficult (orange): 1 or 2 levels higher
• Challenging (yellow): same or 1 level lower
• Moderate (blue): 2 or 3 levels lower
• Easy (green): 4 or 5 levels lower
• Effortless (white): 6 or more levels lower

It should be noted that these distinctions can become largely irrelevant on some local vault servers, simply because a player can edit his character at will and/or give their character items and weapons that far surpass the damage rating system.