Gord's not sure he ought to confront someone who has an artifact in their pocket, but dissembling might be seen as hostile. He hasn't done anything hostile yet, only looked at them. Magic clearly exists in this world, they all have normal magic swords, so they can hardly be upset when a mage notices that they're openly carrying. 

So: don't frame this as a confrontation, and tamp down his fight instincts. He was surprised, not preparing to attack them. (The two can appear similar in a veteran adventurer of the Wound border.)

"Whatever you have in your pocket," he says to Frodo, "is either more powerful than a fifty-foot gemstone that can stop a balor lord (*), or a cunning trap to distract and blind mages. I couldn't help but stare. If you don't actually want people to notice, put it in a lead box."

"...I can't tell how much you could learn, I'm not a wizard and can't teach anyone. You need to find a wizard to ask to learn from."

(*) Large demon, fire and shadow, wings, wields a sword and a whip. You know the type.

Merry whispers in shock, "He - he noticed the Ring.  Somehow.  And how powerful it is."

Frodo's hand goes reflexively to cup over his pocket, and he wishes for a moment he could just slip it on and get away.

"H-how'd you do it?  Another spell?  And what're you going to do about it?"

"One of the most trivial spells that every single mage knows, wizard or cleric, is to detect magic. It only works for a few minutes, so people don't always bother, but it doesn't cost anything and some people have it up all the time. A wizard can usually tell what the magic item does, but I'm no wizard."

"I'm not going to do anything about it, or tell anyone else; I don't even know what it is. I'm just telling you, as a courtesy, that it's extremely noticeable and if your intent was to conceal it then you should do that. I'd further warn you that whatever it is looks very powerful, and is likely to make you a target just because of that, but it sounds like you already know that?" He cocks an eyebrow.

"...also, you all have visibly magic swords and daggers but they're an ordinary amount of magic, same as mine, and no-one would bat an eye at it. Just for comparison."

"Huh!"  Merry's hand goes to his dagger.  His magic dagger.  Maybe he should've guessed that a Barrow-blade would be magic, but he hadn't guessed it.  "I... it isn't ordinary.  And - yeah, the Ring makes us a target.  That's why we haven't been on the Road in the first place."  He pats the mud-stains on his pants.

And then, suddenly remembering, he translates to the Common Tongue.  "He says he's not going to do anything about it and he doesn't know what it is except that it's powerful - well, I guess I told him sort of --"

"Just how much did you tell him?"

Strider gives him a stern glare.

"That it's the Ring -- er, nothing more.  I didn't mention how -"

"Then don't mention it."

He turns to Gord.

"Please do not tell anyone.  We have been trying to keep it secret... despite some lapses before now."

"I won't. ...you should really put it a lead box." Because Frodo is carrying an artifact and he is carrying it around in his pocket.  Gord would offer his, except he got rid of it after he made third circle and got that Divination-spoofing spell. 

And it's apparently a magic ring, but he's not wearing it. Maybe they thought it would be easier to detect if he wore it, and whatever it does isn't usually useful? 

He tries to put the matter out of his mind; it's really none of his business and he's glad the matter was peacefully resolved. "So, um. You said the local gods don't normally choose clerics, except the Dark Lord, but they taught some people wizardry, and all your mages were wizards? What do you do for healing?" If the local wizards can heal, maybe he should just discard all his assumptions.

"He says put it in a lead box...  why!?  And, uh, we didn't bring any of those."

(Then he translates the other question.)

"Huh..."  Frodo's hand is twitching absent-mindedly just under the pocket where the Ring sits.  "Uncle Bilbo put it in a box in a trunk in his study once.  The box might've been lead?  But he took it out long ago... and I didn't ever put it back there myself after he gave it to me.

He stares off into the sky.  "I don't think the wizards learned their magic from the Valar?  Though come to think of it, I don't have any idea where Gandalf did come from.  He's older than... than the Old Took, older than the Shire I think..."

"Yes, much older than the Shire."

He does know where Gandalf is from, but Gandalf doesn't want it brought out as a point of curiosity or undue attention, so he's not going to say it now.

"And he can heal, but no better than the Elves - though it's true the best of the Elf-healers learned their art in Valinor or from people who learned it in Valinor."

"Because then it can't be easily detected," Gord repeats patiently. "And if someone scries it they'll just see darkness. ...actually, you should put it in a regular box, or a good bag that doesn't let any light in, just for that." 

That's the second time they brought up Elves having learned magic in Valinor (from gods?). Some people in Golarion say that elves came from another world; probably they did here too, and that place is called Valinor. And their wizards can heal - maybe not as well as clerics, they probably have spells like the Chelish one but they wouldn't have channels. The Gandalf they've been looking for is one such (old) elf wizard.

It doesn't seem like they know enough about magic (and, by inference, the wider world) to be the best sources of information. On the other hand, if he'd landed on some truly random people they might not know anything beyond their village, so really he had good luck there, even if they're behaving like rookie adventurers who inexplicably decided to start in middle-age. (He's reserving judgement about Strider, and the fourth hobbit he hasn't met yet.)

"So - I'd like to go home, but I can't do it myself, not yet anyway. So I'll be looking for powerful mages to help me; I do have magic enough I could probably trade for it, and someone might be interested in my knowledge of another world. At home I'd look for clerics," because he needs to start by plane shifting to Elysium, "but here I guess I'll have to settle for wizards. Do you have advice on who I should approach and where?" He obviously isn't going to just take their word for it, but right now he is on a hill literally in the middle of nowhere with no other leads except a road that probably leads somewhere. "Actually, can you draw me a local map?"

"Well, I've got it in my pocket now, and you could still see it," Frodo says when Merry translates.

"And we're going to Rivendell, where Elrond lives."  He shrugs.  "I don't know anyone better than him, since we haven't been able to find Gandalf.  And... I don't think I ever had any maps beyond the Shire, except for the ones Bilbo left me, and they only show the Misty Mountains and the places beyond there..."

Just then, Pippin comes running up over the edge of the hill.

He started getting curious and impatient almost as soon as Sam left him with the pony, and it wasn't too long before he decided that they very well might need a fourth Hobbit, given that one never could predict what might get into Big People's heads.

So, he tied the pony's bridle to an old branch, unlimbered his dagger just in case he'd need it, and started up the hill.

But he couldn't keep running all the way, so he started looking around, and then...

"I saw them!" he calls as soon as he's in sight.  "They're here!  On the Road!"

"You saw who?"

Aragorn quickly looks over the whole hilltop, as if ready for enemies to come any moment.

"And where'd you leave Bill?  The pony?"

"The Black Riders!  There're four of them, right below the hill, down on the Road!"

Frodo exclaims in horror.

"Enemies of yours?" Can he see what they're talking about from here?

"Y-yeah," Merry says nervously.  "They tried to kill us in Bree - they're sent by the Dark Lord -"

None of them can see them (or the Road) from where they're standing, but when Strider goes to the far south edge of the hilltop (crouching almost to a crawl so he's less visible), he hisses, "I see them.  Five now."

"If you want to fight them I'll depart or stand aside; if you want something else, I don't know enough about this world to tell which side to help but maybe you can convince me quickly - tell someone in your party to summarize, I can still understand all of you when you talk -"

In fact his Comprehend Languages will soon run out, probably before he can talk to these Riders to get their side of the story, which is a pretty good argument for not getting involved in any actual fighting. He might be strong enough to carry the fight, but neither side knows that and neither does he, not for sure, and 'I am a fourth circle of Gorum' isn't legible around here. If the halflings don't want to fight then he'd like to help them but not unconditionally or indefinitely; maybe he can fend off these Riders until morning, nonlethally, and talk to them then?

Gord crawls the last few feet next to Strider to get a look. 

He sees black specks on the road below - Black Riders on black horses.  They're standing still next to each other at the foot of the hill, as if conferring, or waiting for some thing or some move of the people on the hilltop.

"You don't know -- how can you not know -" Pippin exclaims, heedless of how he'd never heard of the Black Riders himself a month ago.

"Gord's from really far away, Pippin!" he exclaims.  "I don't think you can guess he knows anything!"

Then he turns to Gord.  "They tried to kill us in Bree!  And knocked me out with terror!"