Since Version 0.143.5 of Valheim (see Version History) enemies have an Awareness Indicator above their head.
The following icons are available:
- Yellow: the enemy is aware of your presence, hostile enemies are looking for you; some enemies, such as boar, will instead start to move away
- Red: the enemy has spotted you, hostile enemies will attack you, passive creatures will flee
After an enemy has become aware of your presence (yellow icon), it is still possible to get away and escape before they spot you.
While an enemy has not spotted you (yellow symbol or no symbol), any damage you deal is multiplied by your weapon's "backstab multiplier" which is usually x3. Dealing three times the damage with your bow can give you a head start in otherwise challenging engagements.