Burrowed fighting?

[CIDE]

alright, it's pretty much what it says in the title. How's fighting work while burrowed? Can burrowed creatures attack non-burrowed creatures while burrowed or partially burrowed (without leaving cover/concealment)? How would AoO's work? Could an assassin/rogue sneak/death attack from a burrowed position?

[Feralventas]

alright, it's pretty much what it says in the title. How's fighting work while burrowed? Can burrowed creatures attack non-burrowed creatures while burrowed or partially burrowed (without leaving cover/concealment)? How would AoO's work? Could an assassin/rogue sneak/death attack from a burrowed position?

Being underground tends to present the trouble of visibility and concealment. A creature that can burrow, but has reach, still needs to be able to percieve a target to effectively attack them, or else deal with 50% miss chances. This also means you aren't granted line of sight, or line of effect, which means that watching for 3 rounds for death attack is impossible without adding something else into the equation. Tremorsense will tell you where a person on the surface or in the ground is, but doesn't mitigate concealment, nor does Blindsense or Blindsight.

So, if you're going to fight from underground, you'll either want to go for a hit-and-run strategy, or find a way to have a spotter above the surface to see for you.

Shadowcaster, for all it's lack of usefulness and power, actually has something that's great for this; one of their low-level Mysteries can let you change where you see from. This would let you pop up some distance from your target, cast the mystery, dive back underground and use tremmorsense to guide yourself into position.

You could also go full 'caster and just use AOE effects. Fireball might need line of effect, but things like Wall Spells and similar AOE and control effects can be done off of non-visual perception I think. There's also the option of summoning things from underground and having them act and attack for you while you're safe. A PF Summoner or Druid could use this to great effect.

[Curmudgeon]

Tremorsense is the minimum you need just to get around; that typically comes in 60' range. But to function well you need to see, not just pinpoint a location. A Ring of X-Ray Vision (http://www.d20srd.org/srd/magicItems/rings.htm#xRayVision) comes in pretty handy so that when you're within normal melee attack reach (20') you can see adequately.