In my campaign, there will be several aquatic locations.

Also, one of the undead foes that the PCs will face will have a special attack that essentially "drowns" its victims. Like a supernatural attack that creates water in the target's lungs.

So I have a few questions:

1. How will you determine how long a PC can hold their breath?

2. How will you handle drowning?

3. As for the undead monster, how would you create it and it's attack by using the existing creatures in the bestiary?

For #3, I'm thinking of using the typical zombie, or ghoul, but give it the special "poison" attack of the Skaven Gutter Runner. The change will be the fluff description: instead of poisoned weapons, it will be supernatural drowning. Essentially, fatigue points?

Whoa.

Environmental Damage dice (ToA p.21) work well for drowning. Just roll one every round after say (To + WP) rounds.

As for the supernatural attack thing, you could just do normal damage and call it strange watery attack, or you could do environmental damage dice, too.

Yeah that works.

I ALWAYS forget about that bit on environmental damage.

I guess that I'm still adjusting to the open nature of the rules (which I LOVE, btw). I'm so used to having a table for EVERYTHING.

Environmental damage is possibly my most favourite small rule ever.