I have started a new campain where the players simply go exploring and end up at a planet that is a fudal world, that is post black powder, they are taken in by this burrly hunter slash tracker that is leading them to El Drado, for those of you who do not know El Dradois a city of gold dreamped up by the spanish concestadors, so anyways I need some ideas of what to throw at them, besides highway men and other creachers, so thank you for the help.

For straight up physical threats.

Rival Rogue Traders.

The long (un)dead inhabitants of the city of gold.

The warp tainted mutant descendants of the inhabitants of the city of gold.

The Eldar who show up when some automated sensors relay to them that someone is poking around in their old abandoned city (of gold).

The city of gold is an old Yuvath one and the ruins are hunted by halo artifact beasts.

It has a shrine to the ruinous powers, guarded by fanatical cultists... or worse.

For some mental and moral challenge ideas.

They find something neat but it is to big to get to their ship.

They find something neat but it may be Heretek/Blasphemus/Warp Tainted.

They find something neat but it is clearly owned by another important imperial person or organiszation.

They find something unusual that could be valuable to the right people.. if only they can find them.

The city of gold s an old Yuvath one, and the Rak'Gol have long since laid traps for any who would follow in their footsteps.

It has a shrine to the ruinous powers and some nasty warp entity hitches a ride in some random red shirt so it can get to the players ship and wreak havock.

Let your imagination run wild and do not be afraid to make up aliens/monsters/gear to fit your needs. Also have it be more than just one thing include mixes of different challenge types. Through in twists.. say it is an old eldar city and they come to check up on it only to find the players and cultists there.. nothing says love like a threeway.

Lest your party scare away or mow through all opposition you may want to up the planets/systems technology.

A system with limited stellar, but not warp travel would be a good setting. A few hospitable planets in the system who all wage war trying to find the fabled city and continually undermine each others efforts to find the city and recreate warp capable spacecraft would make a good backdrop. Every 100 years or so they get close but end up destroying each others space craft and ending back up at zero. The party happens to show up on the verge of this self destruction.

Perhaps the war has gone on for so long that one faction knows not why they fight, just that they HAVE to stop the other at all costs.

Human Colonists with weapon styles and cultures unique to each planet.

Orks are always good and can make weapons out of just about everything.

The Eldar have a knack for showing up at the right place at the right time as well, pesky farseer's.

And if you're a mean bastard, the City of Gold truly never existed and millennia of wars were fought over a simple rumor and the real prize is claiming the system itself.

- Assist one side in defeating the other permanently, establish a slave trading route with the victor.

- Bring peace to the system and form a trade route for the systems resources.

Thank you both for the ideas, defentaly good for future campains and more importantly this one, so again thanks.

Keeping with the "conquistadors searching for El Dorado" theme, I'd add some feral natives. These can either be primitive humans (with stealthy ambushes, primitive boobytraps and warp-wielding shamans), or a new xeno species (if you play with miniatures, I'd tailor these to what figures you can get your hands on- maybe Lizardmnen...?).