"I am delighted to see you, Lady Rachel."
"So am I, Lady Isabelle," said Rachel. 'I wish you a wonderful birthday."
The duke's daughter looked at her from head to toe. "Did you grow up since the last time we met?"

(Ah. Let's pray Rachel doesn't respond the same way as she does with me.)

"I wonder... Perhaps you are the one who shrank!"

(And she did, just with a more refined tone than usual. That's not something to say to someone who is not that much taller than me despite being close to twenty. Did she even get anything from those hellish etiquette lessons we went through...?)

Seeing Isabelle de Lockmond's face decomposing, Alice felt like she had to support her friend. "You are surely thinking this because of the contrast with my height, Lady Isabelle."
"That might be so. Lady Alice, this is our first time talking together. It is a pleasure to meet you." 
"L-likewise. I am most honored to partake in this celebration despite my modest status."
"I hear Lady Rachel and you are close friends. If she decided to bring you with her, I have nothing to say."

(She's basically saying she would never have invited me otherwise. Ouch.)

Watching Lady Isabelle leave them to welcome new guests, Alice could see a certain resemblance between her and the departing noblewoman. She was of a similar height, looked way younger than she was, and had green eyes as well. The massive difference was her pitch-black hair tied into one long braid.

(Surely, Rachel didn't approach her just because she looks like a dark version of me, did she?)

"So, what do you think of Isabelle? She is tiny, right? I bet some people would think you two are twins!"
"Listen, Rachel. I know you have good intentions, but do not bring up a girl's height like this..."
"Why so? I think being small is charming."
"Being a little small is not necessarily a problem, but she is at another level! Did you not see how that ticked her when you suggested that she was even smaller than before?"
"I did not... Were you always this observant?"
"Overall Lady Isabelle has impressive control over her facial expressions, but her façade crumbled just enough to show that she was hurt."
"I see... Perhaps you picked up on that because you two are the same, stature-wise."
"..."
"Ah, I think I understand what you mean now!" Rachel said as she attentively examined her friend's expression.

***

On the edge of the immense room within the Lockmond estate where this 'Grand Banquet' was held, Alice was sipping on her liquor against a wall. 

(What purpose do I serve in being here, again?)

She was watching her friend, Rachel de Vallmont, leave for the fourth time to dance with some nobleman she didn't know. As for Alice de Ravendall, she was feeling closer to the orchid-like plant just beside her in that no one had acknowledged her existence even once.
While being given the cold treatment would be unnerving for most people, Alice was glad she did not have to apply all the small-talk openers she had been forced to retain in preparation for this banquet. 
The fewer the opportunities for self-embarrassment there were, the better.
Moreover, she didn't know how much the beverage she was drinking at the moment would alter her dance skills. She feared that the intoxication would, just like in her dreams, make her launch some lecherous choreography while singing a bawdy song that she had unfortunately assimilated. After all, at least in this life, it was the very first time she was drinking alcohol. For now, it was only making her mind go blank in the middle of her train of thoughts now and then.

(Mmh? Am I about to get asked for a dance?)

In the distance, she could see a group of four boys looking at her. One of them, probably the leader, was at the center of the formation and was pointing at Alice while slightly moving his right hand. From the way they were all positioned, it was as if the three lackeys were meant to obstruct the visibility so that other people wouldn't notice what they were up to.

(... I know where it is going.)

Right after she realized it, Alice grimaced as she felt the unpleasant sensation of foreign mana bouncing off her skin, caused by her mana veins rejecting it.

Alice had been warned that she would certainly be subject to that sort of mistreatment. In particular, her mother had suffered from this on several occasions because of her hair. As such, Alice wasn't surprised that people would try to intimidate her for the same reason.
This act of targeting each other with mana wasn't even specific to appearances. Although not a lot of people acknowledged it, it was common for nobles to target those beneath them during noble parties.
It was of course prohibited by hosts, hence the reason it was done secretly.

(Is that twerp from a more powerful family? Well, probably. I'm from a former baron family and this party is supposed to have all the VIPs regrouped together.)

The very fact that he had taken the risk to be seen bullying another noble was proof enough that he was powerful.
As for the procedure to follow in this situation, it was simple.

(If anyone slaps you on the right cheek, turn to them the other cheek also. Is that what I have to do? How stupid.)

Without proof, accusing a higher-ranked noble of messing with her was bound to make the situation worse. And if she were to retaliate, Alice would be risking the four guys to go complain to the host. 
Thus, the only thing she could do was wait until he got bored. If what her mother had told her was true, she might need to wait up to two or three hours until then.
Truly, this kind of attack revealed an outrageous asymmetry. The assailant merely had to move their hand from time to time so that the mana followed the target, playing with the victim for as long as they wanted. Not to mention, the mana they used was invisible and untrackable.

(By using a spell, I could haunt that wimp wherever he goes without needing to move a single finger. Should I strike back after all?)

Alice waited for a bit but, seeing no sign of either Rachel returning or the noble boy stopping, the temptation to do something was growing.

(Ngh... I feel like the situation calls for a mana armor that protects against mana. This is such a stupid idea, but I'm curious to see if it does the trick.)

The main feature of the mana armor spells was that they were continuous, meaning they were constantly active. More specifically, they were recast every so often to look continuous.
By construction, however, the spells in that category had mana as their output form of energy, mostly to cover some of the constant cost. Having mana as the input form for such a spell, however, would result in a self-cannibalizing spell that gets rid of the very medium that supports it. If the problem wasn't treated differently, this spell would be fated to be short-lived.

While making it look like she was redoing her hair, Alice blended multiple specific hand movements and conjured three different mana barriers in the form of concentric half-spheres around her.
The middle layer was the idiotic autophagous spell taking the form of a mana-to-heat conversion, while both the innermost and outermost ones were counterspells in the form of a heat-to-mana conversion.
While the foreign mana passed without any issue the outward barrier, it was subsequently erased from existence as it made contact with the mana-to-heat spell, which proceeded to implode on itself right after. Its ashes, in the form of heat trying to dissipate in the air through both conduction and convection, were trapped between the two other predatory barriers.
In addition to simply reconverting the heat into mana, those two sub-spells played the role of recasting the reborn mana, forcing it to put itself in position before reproducing the last iteration.

Those operations were performed so quickly that Alice didn't have the chance to confirm it was doing exactly what it should. All she knew was that, despite the boy moving his arm in the distance, she was no longer feeling the awful sensation.
Confused about why he couldn't move nor sense his own mana over where Alice was, the brown-haired boy was starting to take more risks of being seen by making wider movements with both hands. This was of course useless since his mana had simply been reborn with a completely different signature and was now added to the aggregation of spells.

(I had my doubts, but this spell might in fact have potential. Should I keep it activated for the time being?)

One thing Alice had not anticipated, however, was the radius of the middle layer, which happened to coincide with the distance between Alice and the plant. She realized this when she started to see smoke beside her.

(...?! C-crap! How much mana did that kid put into the barrier?!)

Alice hadn't sensed any mana boom, so he certainly had used less than the mana in Alice's mana pool. Even then, the houseplant wouldn't have been affected by the local increase in heat.
As she pulled the plant pot toward her so that it would pass through the heat-to-mana, she noticed there were not any obvious burned areas.

(Did it... burn from inside? That would make this spell lethal to living beings!)

"Lady Alice," said a clear female voice. "Explain yourself."

(Mmh? W-wha-?!)

Less than a dozen steps away, the host of the party was walking toward the sphere that could fry her mana veins just by passing through.

"L-lady Isabelle...! Whatever are you referring to...?"

As Alice was wondering if Isabelle was talking about the plant, the spell, or simply the act of defending against a more powerful noble than her, she was also desperately trying to uncast the barriers. The innermost one would be easy to remove, but the outermost wouldn't as Alice's order to stop the spell would have to pass through the mana-to-heat before, eating away the order by doing so.
As such, she was searching for the few holes she had placed here and there in the three layers so that she could uncast the two heat-to-mana at the same time, thus stopping the production of mana and preventing the regeneration of the deadly middle layer.

(And... done! Thank God, she won't die now... So, what does she mean?)

"Playing dumb?" Isabelle beckoned Alice to look at the boy from earlier. "Look at Brangett's state."

Contrary to earlier, the leader, apparently called Brangett, couldn't stand without his friends supporting him.

(... Does she think I did this? He must be faking it! )

"Y-you are mistaken, my Lady! I did not put him in that state, I swear!"
"Mmh? Of course you did not. I did."
"Eh?"
"You should have been in a similar state. Yet, here you are, looking unbothered. Just what did you do?"

(Eeeh?! Are there no decent people in this room?!)