Help! My players need to find a thing!

[BioCharge]

Hey Playground!

So, I'm in a bit of a pickle with some serious writer's block for my next quest and would like some help.

I am running a sandboxy campaign in a world I've written from scratch. The last session, my players solved a series of murders which linked back to an Apostle Kyton (https://www.d20pfsrd.com/bestiary/monster-listings/templates/apostle-kyton-cr-2/) that had been wanting to aid the civilizarion in "ascending" and, blah, blah, blah, that's not important. The important bit is that they found out the Apostle Kyton had been a researcher before his transformation searching for an ancient artefact linked to an ancient form of magic (which is Akasha/Incarnum, though the party does not know that.

The party decided they wish to pursue and find what he had been looking for. I already know what the artefact is, what it does, and whose possession it is in (a Graveknight (https://www.d20pfsrd.com/bestiary/monster-listings/templates/graveknight-cr-2/)). Futhermore, an order of Hellknights are also searching for ot as well. Both groups have tracked the artefact to an oldz ruined city overrun with demons and undead that the graveknight has created.

My main problem is thus: how do I go about having the party finding the Graveknight without it being as sinple as a survival check to simply track him? I would like to factor in it being a sort of race against the Hellknights, but I'm not sure how to model it. I was thinking the skill challenge rules from Rogue Genius games that you can find on the d20PFsrd, but I have no idea how to really format it in a way that makes sense.

If it's relevant: my setting is a dieselpunk setting mixed with heavy fantasy elements, and it's essentially built around Spheres of Power. My party consists of a Raptoran Sentinel, Human Paladin (heavilly rewritten), a Kasatha Armorist (Whitesmith archetype), a Human Incanter (focusing on buffs, very few attack spells), and a Hedgewitch (Spirtualism and Martial traditions). All are level 6, but can punch much higher than their level would indicate (purposely, mind you. I gave them several buffs so they could take on stronger enemies). If more details are needed, just ask!

Any help would be appreciated!

[RNightstalker]

After skimming the Graveknight link, the first thought that popped to mind was whoever became the Graveknight has significance. Not knowing who the Hellknights are, they could be searching to help said Graveknight retain a high position of authority, and the party needs to somehow redeem the Graveknight. A connection to one or both parties and the Apostle could help.

Also, what led both parties to the old ruined city? Did they have different copies of a map with different legends and clues? Have the parties crossed paths before? If you want it to be a race, they need to know they have a capable opponent. They also need to know the stakes, that time is of the essence. The abilities of the artifact can also play a huge role.

[BioCharge]

After skimming the Graveknight link, the first thought that popped to mind was whoever became the Graveknight has significance. Not knowing who the Hellknights are, they could be searching to help said Graveknight retain a high position of authority, and the party needs to somehow redeem the Graveknight. A connection to one or both parties and the Apostle could help.

Also, what led both parties to the old ruined city? Did they have different copies of a map with different legends and clues? Have the parties crossed paths before? If you want it to be a race, they need to know they have a capable opponent. They also need to know the stakes, that time is of the essence. The abilities of the artifact can also play a huge role.

Alright, so to answer some of that:
The Graveknight was originally a test subject for the artefact. The artefact resonated with his species (essentially an animated suit of armor, but connections to Incarnum). The Artefact can syphon excess soul energy (dealing damage) and give the user extra Essentia for their recepticles. Since this world has forgotten what Incarnum was, no one knew what this meant. All they knew is that Graveknight (before becoming a graveknight) could enhance their rwcial abilities after using it. The power surge sort of become an addiction, causing him to drain the life of everyone. Eventually, the chaos he caused allowed demons to overrun the city and lead to its abandonment. He was strong enough to sort of turn the place into his haunt, draining demons for their soul energy. I mostly chose graveknight for the connections to the suit of armor, lacking any other fitting undead type.

Both parties knew the artefact was here from the same source: the Apostle Kyton. The Hellknights were the ones who captured him and subjected him to the ministrations of a regular Kyton. From their they learned of his research and sought it out for power. The party learned after they defeated the Apostle Kyton and taking his journal. Thus, the Hellknights have about a month's head start, but the going is slow due to them not actually know what the artefact was (the Apostle Kyton didn't either, just that it existed) and the constant assault by demons and the Graveknight himself (they do not know it has the artefact).

I plan for the party to encounter squads of Hellknight troopers (essentially stormtroopers) early on after arriving the city, but I don't know where to go from there, which is my problem. The party can theoretically follow a patrol, but only two of the 5 have any real stealth capabilities and the party favors combat. They could capture and interrogate a trooper, too, now that I think of it, but I still have no idea how to really play the rest out.

The importance of the artefact is that inscribed in an ancient dialect of Sylvan is part of an epic poem that leads to a place known as the Wellspring (essentially taking the introducing Incarnum minihook from Magic of Incarnum, if you've read that).

Wow, the situation is a lot more complicated than I thought now that I've written it out!

[RNightstalker]

If the party favors combat, would they be the sort to take prisoners? If yes, then they can interrogate someone from the squad that "greets" them to the city. If not, maybe they carry their orders with them, and it turns into the party having to take out the Hellknights from the ground up.

[daremetoidareyo]

Make a strike force. An opposing graveknight aligned team. Like the opposite of your party. Give each a schtick and a cool name and a personality. Stat them like Pcs. And have the race be against them. They confront each other on the road to get the mcguffin. Don't let the fight be to the death, give the strike force a retreat tool if the tide turns against them. And have this group harry the pcs or force the pcs to catch up.

[Fizban]

I would like to factor in it being a sort of race against the Hellknights, but I'm not sure how to model it. I was thinking the skill challenge rules from Rogue Genius games that you can find on the d20PFsrd, but I have no idea how to really format it in a way that makes sense.
Races can be lost- unless you have a plan for the PCs losing, it can't actually be a race with any sort of mechanics.

[BioCharge]

Races can be lost- unless you have a plan for the PCs losing, it can't actually be a race with any sort of mechanics.

Oh, I 100% do have plans if they fail. How it ultimately plays out with the players depends simply if they continue to follow it. If the Hellknights get the artefact first, the players will constantly be several steps behind them if they continue along this quest chain. I'm open to them not doing so, however. Sandbox campaign and all.