"It should not be long now. We must arrive at Saelon lake first, and then we shall make the change from your world to mine." Saelon was not a word that Eros probably would know; it was not in any human languages or maps. Indeed, none but the Erlkonig and the Fair Folk would be able to find it.
"Understandable. I assume it is a bridge between worlds? If I could, I would absolutely love to study it for some time, both sides of the bridge. I… it would be a highly enriching experience." he said.
The Erlkonig nodded a little. "It is, yes. Perhaps you studying it could be arranged." He replied, keeping an eye out as the stallion raced along faster than any mortal horse could ever have run.
"When?!" she exclaimed, eyes lighting up. "Do you know how it works? Does it perhaps show any signs of Dark energy? Not what I actually call it, but it's the commoner's term and it works well enough outside of an academic setting. A bridge between worlds could easily be a force of Corruptions."
He blinked a few times. "Not for a few days, at least, I do not think. There are other things we shall be busy with."
"Ohhhh…. you mean, the whole marriage arrangement. Yes, that. Could we skip that then?" this was a stupid question indeed, but it was probably the best question Eros could have asked at the time.
He blinked again, shaking his head slightly. "No, we cannot. There are things that must be done that cannot be simply skipped, dear mortal." He kept his eyes on the forest ahead.
Eros groaned and leaned all his meager weight on the man. "Ugh, why? You're really a sore spot, aren't you? You must positively get off on ruining people's fun. Why can't I do my research? Because," and this is when she deepened her already low baritone, "we have to get married and do serious, married people things."
The Erlkonig snorted faintly. "Are you saying you want to do what married couples do? Don't forget that I've been married to plenty of others. I know what married couples do." He smirked faintly, the stallion still racing along below them.
"That's the thing. I've never been a romantic person. I don't think I'm capable of feeling love at all, for anyone, ever. Married life would be the last thing that would suit me, you know." he shrugged, holding on tightly to this mad god, or fairy, or whatever he was.
"It's only for five years, and the purpose is not love." The Erlkonig responded. "You are not expected to fall in love with me, my dear, and I do not require it of you."
"Well that's a relief. So what purpose do I serve, then, and again, what happens to me after the five years? It would be useful to know." Eros said, raising an eyebrow.
The Erlkonig frowned a little, and did not answer, merely leaned forward as the stallion broke from the trees and into a clearing. Before them was a pool that was a deeper blue than the sky above them, a blue that was more than blue, but what else it was would have been nearly impossible to pin down. The stallion did not pause, simply leapt higher than any mortal horse could have jumped, and then leapt into the pool. The water didn't even seem to be wet, though, and within seconds they came out of the water again. But the world they exited into was not the world they had entered from. Indeed, it looked similar, but was not the same. It was night in this world, the sky black and dark. Lights bobbed and slipped through tree trunks, appearing and disappearing seemingly at random. The stallion paused by the side of the pool, snorting and pawing at the ground with a hoof.
"W-what is this place? It's beautiful! I really must stop to study it, may I…" he moved to indicate he wanted to get off the horse, ignoring her previous questions completely in favor of marveling at the sights and sounds all around. Eros gasped as a light flew past, and when she reached out to touch it, it burst in her hand and left a perfect tingling sensation in his hand.
The Erlkonig watched warily. "Please do not touch the lights." He said softly. "They could pose dangerous for an unmarked human. For the same reason, please do not get off the horse. As for your question about what this place is…this is the Underground." He looked at Eros.
"Unmarked? Fascinating. Is a Marking some sort of ward or protection spell you may place on me to prevent certain… tragedies? Death, kidnapping, the like?" Eros asked, raising an eyebrow.
"Sort of. Humans aren't supposed to be in the Underground, and an unmarked human will usually end up dead at the hands of my people. The Marking is part of the marriage process, so you won't need to worry about that for too long." He said, tapping the stallion's side with his feet. The horse snorted, and started to move again. The trees rustled and shifted, faint sounds of laughter trickling through on the breeze.
"Where's the laughing coming from?" Eros asked, hoping that at least some of her questions would be answered by the brooding stranger known only to the world as Erlkonig and that she'd be able to have at least a basic understanding of their surroundings.
"The Forest folk." He said. "Dryads, mostly, at least in these parts." The trees parted to reveal a path that led into the forest, and the stallion walked down the path.