Custom HTHAD monster groups and events

I'm posting a few alternate chart entries and monster groups to the How To Host A Dungeon wiki, so I thought I'd cross-post them to my blog as well. Some, but not all, of these have been tested in my recent playthroughs of HTHAD. (Click here for Index of all my How To Host A Dungeon articles.)

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New Monster Groups:

Delving Groups:

1. Deep Dwarves: Whenever Deep Dwarves patrol, they do not go in a random direction. They head straight towards the nearest ore source they have not claimed, digging a new tunnel if necessary. If there is no ore left on the map, they advance (digging if necessary) towards the bottom of the map.
2. Infernal Automatons: Infernal Automatons ignore (and are ignored by) the Bound Demons of Infernal Engines or the Soul Mill. They gain +1 on Encounter checks if they have any Infernal Engines or Soul Mills in their Zone of Control.

Breeding Groups:

1. Changelings: Start with 2● and 0○. Whenever the Changelings win an Encounter check, both they and the Monster Group they just encountered gain 1●.
2. Kender: Whenever Kender encounter another Monster Group, they first automatically steal 1○ from that group. Then they roll for the encounter as normal, but with -1 on the Kender's roll.
3. Goblin Herders: At the end of their Season, if they are supported, add a Feral Squig ● anywhere in their ZOC. The Feral Squig ● is a wandering monster that ignores (and is ignored by) Goblins.

Alpha Predators:

1. Vampire: Whenever a Vampire would be killed, it actually escapes by turning into a rodent or mist, or by melding with the earth. In any such event, it drops all its loot on the spot, and sinks through the ground to the next open room or corridor below it. If there is no such place within a finger's distance, create a new Tomb one finger below it to be the alpha's new lair. (Mark that Tomb with an X to remember it.) The vampire is only truly slain if it sinks through the ground into magma, the running water of the underground river, or off the bottom of the map.
2. Titan: The act of breaking free from Tartarus unleashes epic devastation. When you place the Titan on the map, roll on the Great Disaster table. The Disaster should run through or be centered on the titan's lair. The titan is not harmed in any way by this Disaster. If magma floods the lair during this disaster, that means this titan is immune to fire.

Wandering Monsters:

1. Rust Monster: Rust monsters destroy any unclaimed ○ they wander over. If they encounter any other Monster Groups, they destroy one ○ (instead of ●). Then, if the Monster Group still has at least one ● and at least one ○ left, the Rust Monster itself is destroyed. Otherwise it is unharmed.
2. Gargantuan: Use a larger-than-normal ● to represent the Gargantuan. The Gargantuan cannot enter any room or tunnel smaller than it's ● in size, including most one-bead standard rooms (like dwarven barracks). During encounters, the Gargantuans kill 2● instead of 1●.
3. Dwarven Trollslayer: The Trollslayer ignores Dwarf, Druegar, Darrow and even Gnome groups, and will move past their entire ZOC in one turn of wandering. If the Trollslayer meets a worthy death while there are any of those groups on the map, the richest one will immediately build a Tomb for the Trollslayer in their territory. Mark it with an X.

Kender are from Dragonlance. Trollslayers and Squigs are from Warhammer Fantasy. Rust Monsters are from D&D, and the Vampire's escape methods are adapted from D&D. All appear here without permission. No challenge intended to copyright, etc. I'm just a fan.

New Special Features

1. Surface War: An army of humans or humanoids, ●●●○ in number, starts at one edge of the map, and marches across the surface until they have an Encounter (which will usually be an Encounter with the Surface Kingdoms). If they find any tunnels, they briefly divert to explore them one finger deep. During their travels, they fight like a wandering monster and loot any unguarded treasure. After resolving their first Encounter, if any of the invading army survives, they build a border Fort. Draw the Fort, up to 3 beads in size as needed, near where the encounter happened. Each turn, if there are one or more Farms within one Finger from the Fort, roll a d6 for each. On a 5+, that farm is raided by the invaders, killing 1 ● Peasant. The Fort ignores other Surface Kingdom buildings, and takes no other actions. Excursions, Adventuring Parties, and Monster Groups treat the Fort as if it were the lair of a group of Chaotic monsters. 
2. Minor Discovery: The group with the most ● discovers or creates a new feature. Roll on the Minor Features chart, and Draw the result on the map somewhere in their Zone of Control. If the Feature you rolled seems beneficial and appropriate, add either  ● or ○ there. 
3. Cave-in: The room or corridor closest to where the die lands becomes clogged with debris and is rendered impassable. Erase it or cross it out. If there were any creatures there, they lose one ●. If this breaks a Chaotic or Hungry groups' Zone of Control into two non-contiguous parts, the group splits into two groups each with half the ● and ○ of the original.
4. Militarization: A random Delver or Breeder monster group starts producing weapons and training for war. Draw a Forge, Barracks or Training Grounds in their Zone of Control. They get a permanent +1 bonus on all Encounter rolls as long as that room is in their ZoC.