He lands on a planet that's all ice and has three suns, which is very pretty. Uninhabited, though, so it's not his next destination—his aura is still flaring. He follows it, crossing interplanetary distances in the blink of an eye, finds the next door's location in the middle of nowhere, and floats/walks through it.
"You're not a big jokes guy, huh." Way: is led.
It winds, up staircases and down corridors and through the curtains-plus-squiggly-little-passageways that this world likes to use instead of solid doors.
And then Tobin leads Sadde through the widest curtain and squiggliest passageway he's seen so far, to a wide semicircular office...
...with a desk in the middle and a woman behind it.
"Hello, Tobin," the woman says. Presumably this is Eleanora. "Who is your companion?"
"My name is Sadde. I'm from another universe. I killed a dragon in single combat and was unhurt. I have other forms of useful shareable magic."
She leans forward and steeples her fingers. "Really. I'm very pleased to meet you, Sadde. Do you prefer Tobin to stay here while we talk or are you comfortable speaking with me alone?"
"I used to be human, but then I became what I currently am. My species—vampire—is ageless, does not need to breathe, sleep, blink, rest, or actually move at all; we do not get sick, we are extremely durable and if you remove a limb we can reattach it—and that's in addition to personal, unshareable magic I have which allows me to manipulate my own biology pretty much without constraints including doing things like regrowing limbs or turning them into spikes which I can drive into a dragon's skull, or generating pretty much any biological matter I want. We are very fast and strong, have much better senses than humans, have perfect recall of everything that has ever happened after we turned into a vampire, have ridiculously accelerated cognition and much more room in our brains. We also become much prettier after we turn. The only way to kill us is breaking us into pieces and setting us on fire.
"Now for the drawbacks. To turn a human they must be injected with venom, which is produced in greatest quantities in our mouths, and then over the next three days the human will suffer agonising crescent pain beyond anything you could possibly imagine or actually endure. It is very common to beg for death. There is absolutely no way I can overstate how horrible it is, and absolutely nothing I can tell anything or anyone that will actually prepare them for how bad it is. Newborn vampires are often so overwhelmed by their new senses that they have a lot of trouble resisting their every impulse, including murderous ones, but this is helped by advance knowledge of it. Newborns are also much physically better—stronger and faster—than regular vampires for about a year after turning. The perfect post-turning memory also drowns out most pre-turning events if the vampire doesn't particularly focus on them soon enough.
"We subsist on mammal blood—but nonhuman blood tastes worse than the worst rotten piece of food anyone's ever eaten, while human blood tastes and smells so good most vampires in my world used to be unrepentant serial killers because of it before the current government took over and outlawed murder. Because of this, it is extremely difficult to turn a human by biting them without actually eating them. Furthermore, drinking human blood makes a vampire less likely to be able or willing to resist it in the future, as well as more feral and antisocial and less capable of living in large groups. There is a set of instincts that completely replaces human ones which also automatically treats other vampires as threats and humans as food. There are associated physical changes beyond becoming prettier; a regular vampire's skin sparkles in the sun, our eyes turn red when we've recently fed on a human, gold when we've recently fed on an animal, and black when we're hungry, and our teeth are much sharper even in comparison with our hardened skin. And a vampire is always at least a little bit hungry, which is reflected in a burning sensation in our throat that echoes the pain of turning and only gets worse the longer it's been since we've last fed.
"When a vampire lays eyes on a person they would be mutually romantically compatible with, they are immediately and eternally in magical monogamous love with them; if the target is also or becomes a vampire, this becomes reciprocal. In case a vampire looks at multiple people they'd be compatible with at the same time, they get this mate bond with all of them. Female vampires cannot conceive, but male vampires can impregnate human females with hybrids, who take one month from conception to birth in a process that often kills the mother if special precautions aren't taken to immediately turn her.
"Any questions so far?"
"In your estimation, could a vampire who did not share your idiosyncratic magic defeat a dragon in the same way you did? What were the biological characteristics, abilities, and limb configuration of the dragon you killed? Am I interpreting you correctly that if an ordinary vampire lost a limb and that limb was destroyed, that limb would not be regrown?"
"Not the exact same way, no, but I expect it would not take much more work—I only resorted to the bone spike after I got fed up with playing nice, but I was not breaking a sweat yet, so to speak. It had two legs and two batlike wings, a long neck, and was somewhat furry. You are correct in that interpretation, but it is in fact rather difficult to remove a vampire's limbs and if they're not actually turned to ash it is possible to pick the pieces back."
"It sounds like the dragon you faced was a type called a wyvern. Most wyverns have breath weapons - they can produce from their mouths dangerous substances, magical or mundane. Most other types are more dangerous and more difficult to kill. Dragon types are most easily distinguished by limb configuration. I can elaborate, if you wish. Dragons are not always made of flesh - some are composed of stone, metal, or more exotic substances. Does that change your estimation? How do hybrids compare with full vampires along the axes you've described? Would sufficient fire or heat kill a vampire if they were not broken into pieces first? Can vampires be harmed at all by extremes of cold, or by acid?"
"If these exotic substances are significantly harder than diamond that might make it more difficult but I expect a dragon would need to be perhaps an order of magnitude faster, stronger, tougher, and smarter before it posed us a serious risk. If the heat was sufficient to turn the vampire to ash on the spot that would kill them, the breaking-into-pieces requirement is just so the vampire can't put the fire out very quickly. Extremes of cold do not harm us, regular acidic substances do not either.
"Hybrids are... less physically enhanced than a vampire, but much closer to that than to a human, definitely much more than just halfway along. They also only retain perfectly memories which they choose to, have less attentional capacity and brain space, need to breathe, need to sleep—and in fact their need for sleep is a bit of a problem because although they sleep less than humans they always need to sleep every day at exactly the same time and wake up at exactly the same time and what time that is varies from hybrid to hybrid. They can also eat regular food and bear children and do not have mate bonds. That's half-half, though; other fractions of hybrid are different."
"Suppose a dragon was capable of keeping you on fire, by sustained application of a breath weapon, but not capable of turning you to ash instantly. Could this kill you? Can parts of your body be burned away without destroying you entirely - either an extremity, or a layer of skin or flesh over your entire body? Some types of dragon don't keep their consciousness in their brains, and need to be killed by destroying a large enough fraction of their body; would a vampire be able to do so? How does vampire venom interact with non-human animals?"
"This could kill me, yes, but the dragon would have a hard time keeping me in this situation. Well, this could kill a vampire other than me, I'm personally all but fireproof. A vampire should be able to destroy arbitrarily large quantities of dragon modulo aforementioned concerns about the possibility of much greater durability. Vampire venom kills animals."
"Not unassisted, not normally. There was one with idiosyncratic magic who could, and I can grow wings..."
"Does idiosyncratic personal magic come with vampirehood or is it a product of your world of origin? You can't regrow limbs, but if you can heal fractures you must be able to regenerate flesh to some extent; could you regrow a layer of skin that a dragon burned off during battle? A layer of flesh? Can vampires receive transplants, either by reattaching somebody else's arms as you would your own or with surgical intervention? Can vampire venom be siphoned and stored? You say you can generate biological substances; does that extend to magical biological substances other than vampire flesh?"
"It is a product of my world of origin but sometimes vampirehood enhances it where it existed previously or creates it where it did not. I am not sure whether that was a property of my world, this is the first world I'm visiting where offering people vampirism is an actually appealing option. Layer of skin—probably, layer of flesh, probably not. Vampires can't receive transplants, other vampires' venom—which coats all organs and which is necessary to reattach a lost limb—burns us. Vampire venom can definitely be siphoned and stored but it's extremely corrosive to most materials, glass being the outstanding exception. As for magical biological substances, I have not yet been able to find a pattern on when I can or cannot create them."
"Do you know by what mechanism other vampires' venom, but not your own, is dangerous? Is one of the magical substances you can create vampire flesh, and if so could you use that to contain vampire venom? Does vampire flesh separated from its body of origin die or decay? Could you create another vampire's venom, or does any venom you produce by any mechanism count as your own? Are there any other useful magical substances you can create and would be willing to manufacture for us?"
"I do not know why other vampires' venom is dangerous and I cannot generate any but my own. I can generate my own flesh, though—or bones, probably better—and use that to contain vampire venom. Vampire body parts never decay—they may dry up if not envenomed but can be restored later. None of the magical substances I've been able to produce are in themselves useful, they are typically only magical in conjunction with other things or used as part of larger magic."
"There was a witch—someone with a magic idiosyncratic power—who could completely shut out all senses of people in an area around him, including stuff like proprioception, but that's the only known method."
"If it's magically possible at all I'd expect it to be possible to engineer a way to do it using Wellspring plants, but that isn't my area of expertise. Now, you mentioned you have other forms of shareable magic as well?"
"Indeed. It's really just the one but it's versatile enough to be able to do pretty much anything. It's called sorcery, and from the moment I walked into this dimension everyone in it was able to use it."