General POV
"No it's not the Holy Grail containing Jesus' blood, this is the Holy Grail that grants wishes, it's different and explaining it would take a lot of time I'd rather do something else with. This is the Holy Grail War, where 7 mages fight a death battle," Rin patiently summarized it when Shirou suddenly banged the table with both hands!
"You can't expect me to believe that! And why would explaining the difference take a lot of time?!" Shirou objected immediately, not wanting to believe that a death battle is ensuing in the middle of this city full of innocents and non-mages powerless to defend. "Firstly, I'm telling you the facts firsthand and secondly, you've not even covered the basics of magecraft and so you won't even understand the difference between the Holy Grail and the Holy Grail."
Shirou gritted his teeth, knowing well what Tohsaka said is right on both accounts. "You should've already known yourself considering the fact that you've almost been killed by one. I am as well on of the mages chosen for this Holy Grail War. Think of a servant as a familiar granted to assist the pursue of the Holy Grail as well as making sure their master doesn't die."
"Saber doesn't look like a familiar, she looks as human as us," Shirou gazed over at Saber with respect remembering how she saved his life. "Servants are technically and magically familiars. But, they are actually superhuman beings, heroes from the past," Rin nodded at Shirou's incredulous look.
"Servants are heroes born out of legends and myths. From the past, present and future, servants remain heroes summoned to our time as partners after the Grail. It is a prime job for us masters to be the one summoning them. Once summoned, the grail shaped and kept them in their true physical form."
"But, servants can shift into spirit mode, remaining invisible and should the time come for emergence of use, you can materialize your servants and command them to fight," hearing that, Shirou looked above to the ceiling. "So, that red guy can change between spirit and material form, as well as the Lancer guy," Shirou eyed Rin for confirmation as she nodded and introduced, "That's Archer, I'm having him keep watch outside while we talk."
"Anyway, got everything so far?" Rin inquired as Shirou hesitantly said, "Sure." Clearly an answer that Rin expected, she added more, "For more detailed and informational accounts, you should talk to the man overseeing this entire war. But needless to say, the outcome for you, Emiya remains one, you have no choice but to fight." After saying the ominous line, Rin poured herself another cup, clearly enjoying the tea way too much.
"Well, onto another point. From what I've heard from Emiya, you weren't summoned correctly, Saber?" Feeling the empty teapot, Rin made herself at home by refilling it her own by the kitchen and Shirou can't even complain. "Yes, By description, I was summoned without any summoning chants nor proper mana flow. Fortunately, mana remains stable and I am definitely supplied. A downside remains, I'm unable to spiritualize myself."
"Hmm... More good than bad, much better than I anticipated, especially since Emiya here seems like a total novice. A servant needs to be supplied of mana by the master and it appears you're totally competent and well in that regard. But I wonder, what makes you so forthcoming with me?" Rin sat back down, her eyes on Saber.
"Admitting that I have mana stability isn't a secret at all and my inability to spiritualize is sure to be discovered within a few days. In which case, it would be better to give Shirou further understanding of the matter at hand, one way is to let you, an enemy know more as to reciprocate," Saber proudly provided, smiling at Shirou, making him blush a tad bit.
"Such dignity as well, it would be great if you were my servant. Fortunately, I'm quite satisfied with my own servant," sighing loudly, Rin went and drank some more of the tea in big gulps, not worrying of scalding her throat. "Are you indirectly saying of my unworthiness as her master?" Shirou can sense the mocking tone from Rin.
"Of course I am, you cheat!" Rin pouted as she pointed accusingly at Shirou. "HAH???" Shirou's face contorted into hilarious disbelief as he went speechless at her total reversal in characteristics, different from the Tohsaka of school, elegant and courtly, this one is shameless and dare he say, rude.
"Well, considering that you have oh so generously and gracefully invited me inside for some delicious tea. I only thought it was fine for me to repay the favor by taking you to see the current overseer and supervisor of this Holy Grail War. I mean, you want to know the reason behind this war, no?"
"Well... I'd like to, but it's late," Shirou pointed at the clock, hour hand at an hour past midnight. "That's fine, but what says Saber?" Rin purposefully teased, knowing it would rile Shirou up, and it did. "Hey! Leave Saber out of this, don't try to strong-arm her," Shirou defended, raising his right hand as a blocking motion.
"Oh? So you can act like a master, you don't want me talking to Saber?" Rin half-covered her mouth by a sly hand, shit-eating grin behind. "Why do I care?!" Shirou blushed as he turned his head, wondering, 'She really isn't the kind Goddess portrayed in school'. "But Saber's a past hero right? She's not going to make sense of the future world!"
"Especially looking at her, a Westerner, wearing medieval armor and fancy dress, I'm sure she hasn't ever even heard of Japan! I mean, she's speaking Japanese, but- but-" Shirou dragged his hand up and down the sitting Saber, showing her garbs while trying to find any viable reason for how the clearly non-Asian servant from the past could speak perfect modern Japanese.
"I'm afraid you might be mistaken Shirou."