So I want to create an endeavor that involves tyranids, but I find my knowledge of them is lacking. My plan thus far is to have the RT scout a previously 'unfound' system which happens to have an ancient city of humans living on it, cut off from the imperium for a few millenia. I'll probably throw some problems the colony is having at the group, orc invasion or heretics or civil war, but I was thinking there would be an archeological dig somewhere that found either an ancient tyranid (encased in ice or somehow in a form of stasis) or some sort of tyranid thing that would attract more of them. Do either of these seem plausible? I have no clue on how the hive fleets work, if they just randomly show up and start eating everything, or do they send 'advance' teams to infiltrate? Or is possible that this ancient tyranid can somehow attract a hive fleet? Thanks in advance!

Well, you've got a couple of options open to you. One is a crashed ship that contained some gene stealers which would set up a cult and send out a signal to the hive fleet. Or a ship carrying specimens from the Jericho reach could have crashed... A whole hive fleet is probably not what you want as it is beyond almost all rogue traders to deal with.

Hive Fleet 101: Genestealers infiltrate a civilisation, spreading their influence across the planet. After the cult reaches a critical mass, the gene-stealer patriarch activates a psychic beacon, which draws the hive fleet towards the planet; this has the effect of acting as a homing device for their super-luminal gravity slingshots and letting the hive know that there's enough biomass available on the planet. Cult then starts an uprising to weaken the planet's defenses before the fleet arrives.

fourtykiller said:

Not to say you can't use the idea of an ancient Tyranid artifact, but the Tyrands (so far as we know) come from some place outside our own galaxy. To find an artifact that has been buried here since any time prior to the current invasion would imply that the Tyranid attack is somehow cyclical. That's a pretty awesome idea for a plot, IMHO, it's just a question of understanding the implications you're making by using a plot device like that.

Tyranids use genestealers as advance scouts. They make their way to a galaxy in advance of the hive fleets and start infecting the organisms they find, setting up genestealer cults and that sort of thing to prepare some kind of insurrection before the fleets arrive. Finding evidence of genestealer activity, past or present, is certainly plausible. I don't know that uncovering such evidence would result in an immediate Tyranid response of any kind, though.

Tyranids don't think like we do. They're all one giant organism linked by the hive mind. I seem to recall some fluff in 2nd or 3rd edition that described the invasion of the various hive fleets being akin to a giant maw taking a bite out of our galaxy. The first fleets came in edge-on, later fleets came down from above and up from below the plane of the galaxy to cut off the sector(s) they had surrounded. It's like the whole fleet is acting like one gigantic creature attacking the galaxy as a whole. From our perspective (particularly early on in the invasion timeline) it might appear that the hive fleets are appearing out of nowhere and attacking planets at random, but they do actually use a pattern. It's just pattern on a much, much larger scale than humans are used to considering.

I also seem to recall some kind of telepathic blackout they generate which makes communicating or navigating the Warp near a fleet difficult. You could set up a plot where the PCs (or the person who hires them) has noticed some sort of unusual Warp activity nearby and they go to investigate. When they arrive they find a planet under attack by a single hive ship or something. An early precursor to a larger hive fleet, perhaps, or a wounded ship that has strayed off course. Even a single wounded ship would be a significant threat for a group of PCs to deal with, especially if they don't know anything about Tyranids beforehand.

You want to be careful about bringing an entire hive fleet to bear, though. That's not something that a small group of heroic adventurer types can reasonably fend off. A single hive fleet has been known to destroy entire Space Marine chapters (or almost, since the Imperial Fists seem to have been retconned back into existence.) Also, whatever is attracting the Tyranids would have to be something REALLY special to make a whole hive fleet change course and come after it.

Thanks a ton for the help! That all makes a lot of sense. I was hoping to use other tyranids other than just genestealers for the adventure, thats why i was thinking maybe a hive fleet or part of one anyways. But genestealer cult could be fun. Do the other tyranid breeds appear outside of a hive fleet or tyranid army ever? I would like to have something other than just genestealers if possible, but if thats not how they work i can work with it. Thanks again.

The Lictor could be use as "long term forward scout" and a breed of them could be about. The Hive fleet just did not show up (yet).

fourtykiller said:

There's been fluff about Tyranid genera turning up on death-worlds all over the galaxy ( and any planet where they show up, even without the support of hive-ships, is going to become a deathworld in short order ) , and apparently even traveling backwards in time, so it's not impossible.

Well you're in luck, tyranids can fulfil both the suggestions you made perfectly.

First of all they regularly use genestealers as advance scouts that both attract hive-fleets and disrupt the defences on the planet but it sounds like you know about genestealer cults. If you do use a genestealer cult I'd give the lexicanum article a read first.

http://wh40k.lexicanum.com/wiki/Genestealer_Cult#.TwBd-Vu4WSo

If you don't want to use genestealers you could use a lictor brood as they serve a similar role in the Tyranid vanguard. Basically the genestealer cult could potentially involve much more of a political aspect with a greater variety of forces from genestealer hybrids to brood brothers (mind-controlled humans) to the psy-wielding patriarch.

As to ancient tyranids - Decades after Behemoth had been driven from Calth, a band of smugglers stumbled across [a giant tyranid's] body frozen intact in the ice-packs.They thawed it out hoping to get a bounty for the corpse, but Old One Eye's grievous wounds instantly began to heal. It soon awoke and slaughtered the smugglers. Isolated from the Hive Mind a Carnifex reverts to its instinct to mindlessly kill, and so Old One Eye's release heralded a series of Tyranid raids on Calth. Lesser Tyranid creatures such as Termagants and Genestealers, also left behind from Behemoth's invasion, were drawn to Old One Eye's presence as a dominant leader.

So there's support for your idea of ancient tyranids frozen in ice. You could have a couple of big tyranids frozen in ice or ash from a volcano and then a bunch of little ones that have gone feral in the jungles or something.

Fighting a hive-fleet should prove impossible in the context of the 40k universe (Hive Fleet Behemoth fought its way to Ultramar and was nearly victorious despite fighting its way through the full strength of the Ultramarines, AFTER being weakened by the Imperium's policy of exterminatus-ing worlds simply to deny the 'nids food) but if you just called it a " very minor splinter-fleet" and still made it very difficult then you might be able to get away with it. Bear in mind that tyranids are extremely dangerous though.

"I seem to recall some fluff in 2nd or 3rd edition that described the invasion of the various hive fleets being akin to a giant maw taking a bite out of our galaxy"

Not quite, or at least that's not how I've read it. Each hive fleet was a new strategy to conquer the galaxy building on knowledge gained in previous attacks. Behemoth was a direct spear-thrust attempting to bull through the opposition by sheer brute force.

When that didn't work the next hive fleet (Kraken) used genestealer cults and infected administratum officials to weaken defences on the Easten Fringe before it attacked in the form of countless splinter fleets across a broad front such that there was no single force for the Imperium to defeat.

The subsequent Leviathan hive fleet attacked from underneath the galactic plane to avoid the defences along the Eastern Fringe. It also split itself into two prongs with a broad space between them. This stretched the Shadow In The Warp (the psychic shroud that accompanies hive fleets and blocks all psychic communication and cries for help in the area they're attacking) over a great swath of worlds AND (thanks to the angle of attack) threatened the astronomicon itself.

One of the backgrounds for a ship can include Planet-bound for Millennia . If that ship (which can be covered in silt at the bottom of a large lake) had genestealers on it, you have an easy cult of 'refugees' that can pop-up on an otherwise backwater world.

Another option might include the vessel of a (heretical?) Magos-Biologist that is pulling samples of Tyranids back from the Jericho Reach and seeding an isolated world/moon in the Koronus Expanse for the purposes of creating an environment to study them under controlled conditions. Now you have a relatively isolated Tyranid threat if you can manage to get the players to the world...

Another idea is that the Beast House are making creatures that resemble type of Tyranid in outward appearance, That way you could have a lab and testing ground somewhere hidden in the Koronus Expanse that is breeding creatures that look an act like various Tyranid breeds (but you could modify their stats as suits).

This would eliminate the having to deal with a Hive Fleet problem and coud lead to some interesting Rogue Trader style adventures (or even have a Deathwatch mission (as a side adventure) to destroy the Tyranidesque breeding facility).

I hope this will help.

In ITS, there's a sidebar detailing how the beast house sends out mercenaries into the Rubicon system to pick up Genestealers from an abandoned ship. It even has stats.

Depends on the game you want to run. If you want politics, assassinations and a shadow war, genestealers are great. As the players learn more the stakes get higher until its apparent the sheer scale of the genestealer infiltration.

If you want straight horror or a bug-hunt game, lictors work well. They operate alone, are really, really dangerous and are incredibly stealthy. Great for ambushes, henchmen going missing in the night, that kind of mounting horror.

Or if its a good war you want, how about a terribly crippled tyranid ship coming into the system and crashlanding upon the planet. The beasties within are disrupted, many are destroyed and the ship is slowly beginning to heal itself. The RT and whatever allies he can muster must destroy the ship and the beasties within before they can get their act together and swarm the planet.