Thouls

Thouls are undead abominations. Patchwork creatures, they possess a strangely refined version of the canibal cravings of ghouls. They will chew off a part of a victims body, eat it and then remove and sew on that same part from their own body. The victim will then become a thoul, filled with a similar craving. The thoul's own body will regenerate, though that part of their body will be larger or somehow more mishapen than it was previously.

Thouls are incabable of speaking the truth.

Zombies

Zombies in the land of the dead are very rarely of human corpses. Large and exotic zombie beasts are seen in herds or alone on occasion. These creatures are passing fads among the Lords of the Underworld. Now it may be a status symbol to have the largest herd of zombie stegasauri, but next week it may be more fashionable to have a single large zombie tiger, trained to perform tricks.

Among the Lords of the Underworld, as in the World We Know, there are those who cling to yesterday's fashions.

Hobgoblins

Hobgoblins are goblins who have been forced to wear shoes. This contains their wickedness and they grow to be larger than a man. Some particularly wicked goblins will continue growing until they are quite corpulent. Hobgoblins are not capable of removing their shoes.

Hobgoblins who serve evil wizards or witches may be found to have black ooze inside them if they are killed.

Hobgoblins are not often found in the Land of the Dead, to encounter them there is a sinister auspice.

The Shadow Realm III

Eating and sleeping is not necessary in the land of the Dead, but having a meal may heal wounds here. Eating the food of goblins may be healing, but it may also have other queer effects.

The Sea of the Dead III

Hazards on the Sea of the Dead include the Mists, the nightmare creatures born from them, and Wraithwind, particularly if controlled by someone skilled.
Falling into the Sea is near certain death-the Dead are eager for company.
Madness is also an affliction that is common among the few living ceatures found in the Shadow Realm. Clerics of neutral gods with the gift of speaking to the Dead are particularly prone to the Madness.

Bandits and Pirates

Revenge, love, and unhealthy curriosity all may drive men and women from the World We Know into the World of the Dead, but for those who take to piracy on the Darkest Sea, greed is what keeps them in the Shadow Realm.

It is dangerous to be a pirate on the Unliving Sea, but the wealth of the Lords of the Underworld and of the Dead Gods is beyond compare in the World We Know.

Bandits in the world we know are as heartless and foul as pirates of the dark sea, just without a ship and a far reaching ambition.

Pirate Ships in the Underworld are strange kingdoms where men an women from the World We Know may work alongside undead or creatures from the Mist.

Magic

In my regular group we have been using Arcane Stress for a while now. I guess since 2011. Yikes.
It works great and does what I want it to do, which is make magic a bit more powerful, weird, and dangerous while changing as little as possible of the regular BX Vancian magic system. The way it works is Magic-Users cast spells just like they normally would in your old school system of choice. If the want to cast any more than they normally would be able to, they can try but they've got to roll a D6 on this table:

1d6	Spell result:
1	Fails. Caster is knocked out d4 turns.
2	Fails.
3	Mutation. Roll on the Spell Mutation Table.
4	Cast at ½ strength.
5	Cast. M-U ages d6 months per spell level.
6	Cast at x2 strength. M-U looses d4 HP per spell level.

Actually some where along the line in the hardcopy I use in game I penciled in some changes:

1d6	Spell result:
1	Fails. Caster is knocked out d4 turns.
2-3	M-U is embroiled in a mystical melee with unseen forces. Roll again next turn.
4-5	Mutation. Roll on the Spell Mutation Table.
6	Cast at x2 strength. M-U looses d4 HP per spell level.

This system is fun because in truly dire situations Magic-Users can take action (magic flavored action) and it might make things worse or it might spectacularly save the day. I changed the table to make mutations more common (because they're fun) but I think the whole idea could be tweaked to be more fun. In my group, when a wizard casts via Arcane Stress it pretty reliably makes the situation entertaining because it is so dangerous/random, but really it is a rarely used last resort.

I feel like it could be changed to make magic more powerful, weird, and dangerous. I've been thinking about this lately because of Brendan's post on Catastrophe Magic. This is a pretty slick roll to cast system. This takes us a bit further from Vancian magic, but it does more to make magic chaotic and interesting without making too much extra work for the player or the DM.

	13	11	9	5	3	1	*	*	*	*
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1

The left hand column is the D20 roll.

The top row is the level of the caster.  

The results break down like this:

	Principal Intensified
	Principal
	Principal and Corollary
	Corollary, Decline and Delay
	Catastrophe

Those are all per Brendan’s descriptions except “Corollary, Decline and Delay” which is corollary and decline plus the spell will go off at the end of the following turn.  After a “Corollary, Decline and Delay” is rolled the MU moves to the next column the next time a spell is cast.  

I’m going to think about this more but I think it could add a bit of interest and make casting get increasingly risky which sounds fun.