How to make a formidable opponent?

I'm thinking about how possible it is in AW to make a single NPC into a substantial physical threat for players.

The non-random weapon and armor numbers, the different PC and NPC damage clocks, and the player moves combine such that any "hard" character who can find a reasonably large gun has the odds stacked well in their favor. This is usually just fine; the "view NPCs through crosshairs" and "do what the fiction demands" principles make it perfectly reasonable for PCs to one-shot most enemies.

A while back, though, I was listening to an actual play podcast where the MC introduced an intimidating character, the badass daughter of one of the campaign's Big Bads, clearly intended as a Dragon. A lot of color went into this character, and then the Gunlugger one-shotted her. I don't know how the players and MC felt about it, but from the audience perspective, it was a little anticlimactic.

So what mechanics exist in AW to keep a Dragon alive long enough to be a threat?
* Numerous bodyguards that will immediately kill you right back if you attack
* Relationships that make killing the Dragon consequential in the long term
* Create special moves that have to be performed before the Dragon can be directly attacked ("To disable the shield generator, roll+sharp...")
* Call for Acting Under Fire before the Dragon can be directly attacked

Anything else?

Players in my campaign, note: this is just purely something I was idly wondering about and has no bearing on anything going on in Merciful Bear don't be silly why would you even think that

Well, first and foremost the Agendas and Principles. The Dragon (I so want to know more about this post-apocalyptic dragon) is subordinate to those drives. Whether the Dragon is difficult or not isn't about the Dragon as much as it is about being a fan of the characters, making their lives not boring and playing to see what happens. The exact same Dragon could be one-shotted by the Gunlugger in one scene and take out the entire party in another, depending upon the fiction you've built up.

That said, things to think of are who's picking the battlefield, what strategies does the dragon employ, Dragon probably acts as a gang, AP Damage, armor. So, yes you may require acting under fire to get to the dragon--like if it's hard to get to them without exposing yourself. But, not just because they're a dragon and thus you always have to roll Acting Under Fire.

Custom moves can also be cool:

Dragon Eye: The dragon's gaze is mesmerizing and hypnotic. Roll + Will, on a 10+ you're able to ignore the effects, on a 7-9 you shake it off after a moment. On a miss, pick one:
*You stand motionless until someone or something snaps you out of your daze.
*You can earn one XP by attacking the nearest ally, anything else is Acting Under Fire.
*You run screaming from the room.

I'm explicitly talking about a TV Tropes Dragon here, not a Dungeon World "16 HP Dragon". :) There are some similarities in this context, to be sure!

I think that this is primarily a storytelling question. The answer why any antagonist is a danger is due to the circumstances that the heroes (or in this case, PCs) are allowed to interact with them. Only introduce a blatantly antagonistic character you want to have stick around when the PCs are incapable of dealing with that threat. Have the dragon meet your gunlugger when she's been captured and is at the dragon's mercy. Or have the dragon have some form of information that the gunlugger needs, so killing her would be a decidedly bad idea. Hell, have the dragon try to recruit him! Why not?

Certainly custom moves are important as well. Give her the inverse of a playbook move, stuff that keeps her living. The Faceless is great for this. Take a look at Pit bull:

Whenever you take a debility, name the person you hold most responsible.
Take +1 ongoing to all rolls versus them, forever.

This is a move designed to make the faceless want to take debilities, by giving him a benefit for doing so. How can we manipulate this to work for our purposes?
How about:

I Can Make it Worth Your While...

Whenever (insert dragon's name here) would die, the killer has the option to instead take +1 ongoing for all Hard, Cool, Hot, or Sharp rolls versus them, forever.

This move gives an enormous incentive for players to keep this character alive. You get to knock this guy about over and over and over again. To be fair, this move facilitates the character becoming weaker over time, but that might be what you want! It sort of reminds me of what Bowser has become in Mario games. He's just less and less of a threat.

There's likely a more elegant move that could work properly, but I think that your best bet is either to only show the dragon when the PCs can't kill him (not that fair, and against the principles if you do it more than once, probably) or create some custom moves or relationships that are less of a barrier for the players, but instead incentivizes them to keep the dragon alive. That seems more interesting to me, personally. Also, don't get too attached to NPCs, like, ever. Because we shall all perish in flames.

Hope my ramblings are of some use! I think the scenario you described was pretty funny, however. Reminded me of the famous sword fighting scene from Raiders of the Lost Ark.

It's perfectly okay for you to create a mechanically tough NPC. Create her as unkillable as you want. Being a fan of the PCs and looking at your NPC through crosshairs just means saying to yourself "she's fricking unkillable. Maybe they'll think of a way to kill her! That'll be cool. I can't wait to see how they deal with her!"

Give her custom armor bonuses. Have her count as a gang. On her little threat sheet, write that the world's psychic maelstrom keeps her alive and rebuilds her no matter what physical damage she takes, so that she can only be physically killed if she's somehow isolated from it. Or you know the "when an NPC takes harm" table? Write a new one just for her.

Then all you have to do is sell it at the table with visuals. The first time they meet her, don't hold any of it back from the players and don't deny their expectations. Like, "you had her, you hit her with a full 3-round burst right in the center torso. She should have gone down. She didn't. There's blood on her clothing but she didn't even flinch. She's looking you straight in the eye. What do you do?"

-Vincent

Players in my campaign, note: this is just purely something I was idly wondering about and has no bearing on anything going on in Merciful Bear don't be silly why would you even think that

So you are saying that reenactments of The Neverending Story style dragon rides are totally out of the question, no way, no how, whatsoever, end of discussion? 

Challenge accepted.

I originally posted this in a different topic about custom moves for NPCs, but it is appropriate here so I'll cut-and-paste. It is exactly what vincent is talking about with changing the mechanics of how you handle assigning Harm to an NPC:

Here's a potential custom move for a Warlord threat, let us call him "The Humungus."

The Humungus is one tough sonofabitch.  He tracks Harm like a PC.  Further, any time the Harm inflicted on the Humungus would go past 9:00, roll+Hard.  On a 10+ he takes the Harm as established.  On a 7-9, his Harm is limited to 9:00, but pick one:

• The Humungus is shattered: The Humungus loses his taste for the fight, at least for now. He flees/retires/pauses to lick his wounds. Create a new threat countdown for The Humungus starting at 0:00 - he fucks off until that counter is filled. Advancing this clock a tick is now a Threat move.  (This gives the players a reprieve from the predations of this particular Warlord threat for a while).
• The Humungus is crippled: The Humungus breaks and shows weakness. Some of his warriors take this as a sign that he's not fit to lead and break away from him. Reduce the size of The Humungus's gang from large to medium. A cruel MC could add one or two new small gangs as emergent threats, or not. (Either way, it reduces the size of the rampaging horde and exposes them to the possibility of defeat in detail.)
• The Humungus is disfigured: The Humungus loses most of his nose, making him one ugly dude and giving his voice a reedy quality. He is surprisingly self-conscious about it, and players may take +1forward in any moves against him where cracks about his appearance can be brought into play (such as manipulating him into overreacting; "That's tough talk from a dude who sounds like a cracked flute").
• The Humungus is broken: The Humungus has taken a pretty serious blow to the head. He wasn't all there before, and now he's mostly somewhere else. The players take an +1 forward any time they are making a move to outsmart The Humungus. (This gives crafty players a better chance to defeat The Humungus using cleverness rather than straight-up brute force, or at least to maneuver him into a position where force will be more effective).

On a miss, he's so damn tough that damage past 9:00 is discarded.

This makes the NPC a little bit tougher individually, but also includes mechanics to alter how he functions or make him a recurring villain.

Here's a potential custom move for a Warlord threat, let us call him "The Humungus."

The Humungus is one tough sonofabitch.  He tracks Harm like a PC.  Further, any time the Harm inflicted on the Humungus would go past 9:00, roll+Hard.  On a 10+ he takes the Harm as established.  On a 7-9, his Harm is limited to 9:00, but pick one...

Oh, I like that a lot. It bridges a lot of the gap between a PC and NPC.