Originally posted by Weaver:

When you aren't around the area doesn't exist in a dynamic sense. It's paused and nothing can happen, it doesn't exist in game without a player nearby. So those things are only happening when you are near them. They can load in fairly far, 60m+ at least so you need to a) have walls and such and b)inside those walls have no spawn items so enemies can't spawn inside while you approach.
( https://valheim.fandom.com/wiki/Player_base )
That Ward protects nothing from damage. It prevents other players from opening stuff or building/deconstructing via hammer, and chimes with a blue aura whenever anything in its radius is attacked/damaged.

Originally posted by DeMasked:

Skeletons might aggro your base if you are near a Black Forest or have killed Bonemass in which case Skeletons can then spawn in the Meadows. Skeleton Archers are probably what destroyed the hives.

Walls, moats, earthen ramparts and anti spawn buildings like workbenches can help deal with outside enemies.

cool thanks, that helps, I'll try to build more. thank you for tips.