Nirth: How does invasion works? I don't own either games actually but I was merely curious as the jump-in-and-out multiplayer sounds quite interesting but I would likely lose interest fast in case someone joined then destroyed whatever progress I had tried to acquire for several hours.
the souls games constantly autosaves and you don't lose anything you picked up if you're killed, besides souls which are used both as currency and leveling up.
If you die, all your souls drop on your bloodstain where you died, but you can get them all back if you can get back there before you die again.
You'd also get kicked back to the bonfire, hollow out an increment (altering your appearance and temporarily reducing your max hp until you use an item to restore your humanity) and enemies would respawn. Though, I should point out that in DS2 enemies only have a limited number of spawns so you can depopulate an area (unless things have changed since the patches) and if you're worried about losing your humanity or are carrying a large number of souls you can just equip the Ring of Life Protection since it's repairable this time around.
it's pretty rare in ds2, though. You mainly just have to worry about it in the bell tower covenant and rat covenant areas.