Invisible

For players
If players turn themselves invisible, most monsters won't be able to see them. For other players and themselves they're visible as sparkling in the air. Also players can't be attacked physically when they're invisible, the only way to attack them is via magic.

Ways to get invisible for players are the spell ("utana vid"), or the stealth ring.

For monsters
Some monsters can also be invisible. This way players can only sometimes see them as little sparkling in the air. You can make them visible by using magic on them, but it's of course hard to hit them with any rune but GFB's. Invisible monsters can get very dangerous, especially if you don't have runes with you to make them visible. Invisible monsters don't appear in the battle window.