Indecision about the design...

Hey Gimmy!

Yeah the theme sounds great, and could provide some interesting gamplay. The Cave that is being fought over could also be something else, an Orcish holy spot, etc. The orcs would be fighting over the right to exert their rule over the other tribes (Players).

I really like the idea of having two areas of conflict - the Cave, and the surrounds (villages etc). Maybe each Orc tribe has their own camp as well, which other players can raid, though they can't afford to make major assaults on them.

One thing that you will have to think about are timeframes. How long would each turn represent? If a turn was a day, then you could have units that go out raiding be away for a turn or two before they are again useable. But then how to do manage the movements and conflict in the Cave?

A few logistical things to work out but I think its a fun starting point!

I like your idea so far, and it is logical too. Once you step into the realm of the fantasy genre, logic can take a backseat anyway though, in my opinion!

With the cave - are you going to have tunnels etc. too, or is it just one big area? Do tribes explore as they go, or is the layout already known?

If its broken up into smaller areas, with rocks/walls in between, you could introduce line of sight rules, which would make it a bit different than an outdoor board. It would help differentiate areas that a player can control - one dead-end could have a source of water, a narrow tunnel might provide a source of energy-lichen (power-up!), a column-filled grotto might also have a small gold vein, etc. Nothing to take away the lure of raiding villages, but maybe just interesting enough to consider dividing a player’s tribe even more…and these smaller areas may be a way for a tribe that’s fallen off in numbers to climb back into the game, if they’ve fallen behind.

Then the main area could be bigger and more open, so conflicts are also bigger, but maybe also worth a lot more victory points. Or possibly maintaining control of the central area gives you VPs based on how long you can control it…sort of a king-of-the-hill thing. One tribe might hold if for a while, but doing so takes a lot of troops, who are therefore unavailable to replenish the tribe’s food stores…how many orcs will the player start sending out to forage, and how long before other tribes are strong enough to take over?

When a tribe's proven they are the strongest (certain VP level is reached), the others must bend the knee!

How about this:
The troll-cave is a warren of caverns and tunnels. Something like this ugly picture:

In the corners are each player's headquarters. The exit of the cave is in the middle of the board (black circle)

To gain control of the caverns (the colored circles), players must have trolls residing in that cavern.
But if trolls make their nest in a cavern, they will need enough food to keep them alive. So trolls must leave the cave and raid vilages (for a number of turns). At the end of each round, you will count your food (villagers) and feed your trolls, or else they die...

Next turn, the trolls that resided in a cavern, have babies and multiply...

The caverns fill up with trolls and then you can expand into other players caverns. There you must fight each other for control of the cavern.

The more caverns you have, the more trolls will need to get out of the cave to hunt villagers (and have less trolls to defend the cave)

Cheese!

How about this: If you control a cave and you were able to feed all of your trolls at the end of your turn (no troll died), your raidng trolls in the villages will capture a troll from another player (that is also raiding villages).

This way, your troll-population grows (more food needed!) and you make it possible that the other player will not bring back enough food, because one of his raiders is captured and working for you now!

If you want more troll-population-growth, you can capture one raiding troll from another player and bring in two extra trolls. (out of thin air kinda...)
After all, trolls will die sometimes from having not enough food...

Cheese!

Oooh, a name game. Lemme try!

"Skull-crusher comes to Fungustown"
Catacomb Court"
"Boss o' Hollow"
"Rockwall Junction"
"A Tale of Two Cavities"
"Big-Dark Crowns a King"
"Underworld Overlord"
"Lava and Lichen: An Orc-Lord's Story"
"Lavababies and Lava Babes: Breeding in the Underdark"
"Damp 'n Dirty"
"Guano and Gunless: the Rise of the Orcish Industrial Age"

Hmm... The last about an orcish technological revolution is sort of cool. A lot of gunpower could be made in a cave-empire.

And TNT blasting would be an issue... hmm...

"Miners and Minors: Breeding and Expansionism in a New Orc World"