What had he been expecting? If there had been any notion of an answer that he had conceived before this moment, it vanished as soon as the screen of fog appeared. Similarly, any surprise that he might feel from the arrival’s small stature or general appearance is obscured by another, singular feeling.
The newly manifested figure faces a young man who appears to be in his early twenties. A single braid secured tightly but nonetheless with straggling strands on either side rests neatly on the side of his face. His eyes, a prominent rosy pink in hue, stare through the fog with what seems to be an almost child-like awe. It takes him a moment to be able to speak, but when he does, his voice has a resounding clarity. 
“Yes.” He states this with a lack of hesitation that almost seems unbefitting or inappropriate. But as if that brings back some unseen aspect of him, his left hand–which had been holding onto the clasp of his cloak–tightens once more. Meanwhile, his other hand is leveled so that it subtly returns to his side. A symbol of some sort can be seen around his hand and the base thereof, though it seems not yet fully formed.
“My name is Sunshine,” says he, maintaining eye contact with the figure despite their differences in stature. “Sunshine Meep, or Sunny for short. I remain a mage in study, but there would be no greater honor for me than to partake in this Holy Grail War by your side.
If you would, may I know your name?”

"Of course," he answers. It may be that he indeed meant the latter in his original intentions, but he seems to have immediately deemed it unfit to press the matter. "Anything else would feel wrong to me instead, though I hope you will readily inform me if any particular degree of formality makes you uncomfortable."
Though there is a tinge of unnaturalness accompanying the mentioned formality in the mage's demeanor and words--an undeniable fact that manifests through a slight degree of discomfort that he exudes--it is instead more peculiar how quickly the awe he felt and showed upon Caster's summoning has vanished from his eyes. The truth in his sentiment is very real and remains even now, but the fact is almost as if entirely distinct from reality by this point in time.

"I'll keep that in mind," he states, taking the Heroic Spirit's hand. First impression suggests that he doesn't have a very strong grip, but perhaps his downward glance at Caster's hands indicates an alternative source to his weakness. 
"I must admit that I contemplated the possibility of summoning someone of royalty prior to the summoning process," he continues, letting go of the other's hand, "and it was an intimidating possibility to consider. At least for me." He adds, "I have never met someone of the sort even in the current time, so I imagine there would be gaps in my knowledge for what is acceptable or preferred by such a person."

"I'll keep that in mind, but I do hope that those we encounter will find respect in its natural form sufficient." 
Keeping a related but irrelevant topic (irrelevant in his view at least) to himself, Sunny turns to regard the summoning circle he had constructed. The shape is fine, the symbols consistent, and a somewhat long piece of bark rests reverently in the middle of its surrounding markings. He thinks for a few moments, resting a hand absentmindedly on his hip, before turning his gaze back towards Caster again.
"Well, I suppose I should now ask you if you have any preference for what you wish to do next. I am fine with your inclinations, whatever they may be."

"That is fine by me," he responds almost immediately, giving a slight nod as he does so. "I also find the need to explore our surroundings. I have not yet set up our residence, so I imagine this will be a good opportunity to do so."
As he speaks, he realizes that Caster likely has some sort of theoretical knowledge about the area already. The Grail is said to give a degree of knowledge to summoned Heroic Spirits, correct? He thinks he recalls something like that, but he also remembers that he was never able to discern exactly how precise the knowledge would be. Well, at least now he'll hopefully remember that the Heroic Spirit is not a total stranger to the land and manifest that understanding through his actions.
"Oh," he adds, remembering something else that he had wanted to bring up. "I don't know if this is too much, but I had been thinking that since today is the first day of summons, perhaps you would wish to familiarize yourself with the city as well." He tilts his head slightly. "I apologize if this is too structured of an agenda or anything of the sort, but if you wish to, we could enter the city after exploring the area."

The mage is already imagining all the times he will somehow manage to forget Caster is in his spirit form. "No. It will be around our current location."
He blinks a few times quickly in succession, likely an indication that he's trying to think of something again.
"Ah, also, I brought a few outfits with me that you can possibly put on before we enter the city. Though," and he adds this portion as a mutter, "I am not sure if the size variety is large enough."

Sunny is impressively holding in his worry about what constitutes flashy. "Very well, then I believe we have somewhat of a schedule in place."
With that, he turns slightly towards the summoning circle again.
"So then, please give me a moment to conclude our time here."
Upon Caster's presumable agreement, he starts a chant under his breath. It's hard to hear what he's saying, but his pronunciation seems clear at the very least, though his incantation speed can only be described as modest at best. With that, the summoning circle as a whole gradually disappears, slightly warping in shape towards the downhill slope of the mountain, where Sunny placed his belongings. 

When the summoning circle is fully gone from sight, Sunny goes to pick up the piece of wood, which he holds delicately in an almost awkward fashion. Then, he carefully makes his way back to his belongings, where he wraps the wood in a good amount of cushioning material, ties it, and finally puts it back into the bag.
Hey look, his hand movements are awkward too. 
When he's finally done and ready to go, he looks at Caster almost guiltily, probably hoping that the other finds the surrounding scenery more interesting than whatever he's been doing, but he also manages to state "I am ready to go" regardless of what the other is doing. Honestly, what a weird guy.

He pauses. "Perhaps. This mountain should be relatively easy to transverse, but there are better paths to take than others." 
He looks to their right, as if to check again.
"But please travel at your own pace, whether that is faster or slower than mine. Maybe there will be something of interest along the way that I would have otherwise disregarded."

"Alright, but in actuality, I was referring to--"
He stops. Was he really worrying about a Heroic Spirit tripping? 
He was. Upon making the realization, his shoulders slant backwards as he tries in to hold in something. Maybe laughter.
"Never mind. I will not worry, then," he makes out, purposefully turning even more to the right and taking a few steps in that direction. 

Meanwhile, Sunny is trying his darnedest in trying to figure out how long silence periods should last. He thinks there should be some at the very least--he's heard that talking all the time is both difficult to maintain and usually unwelcomed, not to mention unnatural--but he's never been the best sensor for this sort of thing. At least for now, he can preoccupy himself by carefully starting his way down the path, though of course there's also the matter of trying to walk side-by-side with his newfound companion rather than ambling in front of the other arrogantly. And trying not to trip, of course.
Oh, the pains.
Or should one say the plains? From this vantage point, the land below the two seems rather flat, with various varieties of hardy grass covering the landscape along with newly budding plants. A multitude of trees dot the landscape, with patches of woods being more dominant to the right side (where they are currently headed), and somehow the light of the sun makes everything seem even more of a lustrous green. Some small streams of water trickle through the landscape, a good distance away from the paths, and give the impression of leading towards unexplored lands. There are faint sounds of birdsong some distance away--perhaps sourcing from the woods--their notes pretty but casual. They have to save some strength for the rest of the day, after all. 
The Master and Servant seem to be a good distance away from the city itself. None of it is visible even from their current vantage point, at least not at first impression. 

Sunny stops to wait for Caster without even thinking much about it. His gaze reveals that their most likely destination is indeed the "there" in the Servant's thoughts, indeed reflecting the woods and path that he focuses so intently upon.
It's obvious from the young man's stride that he's someone accustomed to walking such terrains. Even ignoring his choice of attire--simple, warm clothing resistant against wear and tear and flexible for movement--he navigates the hillside smoothly, as if the current path they are taking is part of his daily routine. Not to mention, he shoulders his backpack easily, even though it seems to carry at least a modest amount of mass.
Nonetheless, even the surrounding scenery can only do so much to illuminate his demeanor. Instead, he seems focused on a final objective, and his words serve to accentuate that focus rather than break it when he asks Caster, "Where do you suppose we should go once we reach that point?" He points vaguely towards the direction of their mutual "there." "I assume you may have a preference of some sort...?"

"May I ask why?"
Funnily enough, Sunny seems to slow down when he's concentrating. It seems he's genuinely interested in Caster's answer, even though the question itself could be seen as dull or typical. 

"Ah, so you have a preference for sunny days?"
Impressively, the irony of what he just said goes straight over his head.