The card, referred to as a "Class Card," was a mysterious, unidentified object Artoria had possessed at the time of her reincarnation into a devil.
Saber, Archer, Lancer, Rider, Caster, Assassin, and Berserker—the seven Servants of the Holy Grail War were depicted upon these cards. To determine their true nature, and with Kazuki overseeing, Artoria had used the card of her own class—Saber—and transformed into that very princess-knight.
Subsequently, they had tried the other cards as well, 'not without various mishaps', and after an investigation that involved Rias and Azazel, they concluded that the forms taken using the Class Cards likely summoned the alternate Artorias, her appearances and abilities from countless parallel worlds, using her own self as a medium.
The legend of Artoria, or rather King Arthur, branched across many paths. The most famous was that of the Knight-King who bore the Holy Sword Excalibur.
Yet some tales told of her fighting not with a sword but with a bow or a spear, and there were even anecdotes of her being a mage tutored by the magus Merlin. She possessed the innate qualities to handle all seven classes.
It had been her very first live-combat test, but having succeeded far better than expected, Artoria allowed herself a quiet, relieved smile.
"The match goes to the Biblical Factions!!"
Heimdall's judgment rang out. Among the spectators, some let out sighs of disappointment, and some hurled abuse at the defeated Fandral—but the majority cheered the valiant efforts of both combatants, and some even praised the victorious Artoria.
'With Artoria-san's victory, there are now those among them beginning to reconsider the Biblical Factions. If Kazuki-san can truly defeat that monster, everything might just work out...'
"Ha ha ha! That was a rather entertaining fight. Now then, it's our turn. You ready?"
"Whenever."
Kazuki answered the laughing Thor with a grin of his own.
'Kazuki-san... He's smiling, even though he's about to fight...'
The fate of the Open Faction—and by extension, the entire Norse realm—rested squarely on Kazuki's shoulders.
And yet, showing not a hint of that crushing pressure, he faced the coming battle with a fearless smile. Just watching him like that made Rossweisse's heart inexplicably pound, her eyes unable to look away.
"I'll head down first."
With that, Thor vaulted into the air and landed in the arena. A roar of cheers erupted instantly.
"Alright, I'm off."
"Ah, Kazuki-san!"
She had to say something to Kazuki, who was about to fight Thor—that's what she thought, but the words wouldn't come. Before Rossweisse even knew it, she had pressed her lips against Kazuki's.
"Mmnh!?"
"I-It's a Valkyrie's blessing kiss, bestowed upon a hero departing for battle! Since it comes from me, a member of the Nine Sisters, its effect is guaranteed!"
Her face burning bright red, Rossweisse rattled off the words in a frantic rush.
'What am I doing?... Uugh, I'm so embarrassed I can't even look Kazuki-san in the face...'
After a moment, the sound of soft chuckling reached Rossweisse as she hung her crimson face low. When she timidly lifted her head, Kazuki was smiling at her with genuine amusement.
"Is that so... Yeah. I feel power welling up inside me. Thank you. I'll win this and come back, Rossweisse."
"Y-Yes!!"
With a heated gaze, Rossweisse saw Kazuki off as he leaped down into the arena.
"Heh heh heh... That Rossweisse, of all people..."
At that voice, Rossweisse suddenly remembered that Hogun was present in this very space, and realized he had witnessed the entire scene from start to finish. Her entire body blazed crimson.
Landing in the arena, Kazuki exchanged a high-five with Artoria as she walked toward him.
"I'm heading out."
"Good fortune in battle."
After that brief exchange, Kazuki stood roughly five meters apart, facing off against Thor.
'Incredible... So this is the strongest of the Norse realm...'
Thor stood over two meters tall, his frame muscular and powerful. The aura of a battle-hardened warrior and the overwhelming divine energy radiating from him made Thor seem even larger than his actual stature. The sheer intensity that prickled against Kazuki's skin forced even him to feel a primal, instinctive fear.
'Come to think of it, the last time I felt this kind of terror from an opponent... was back then. ...Just how much stronger have I become since that day? How much closer have I gotten to that person—to Sirzechs? I'll use you to find out—Thunder God Thor!!'
His resolve set, a crimson aura like blazing flames erupted from Kazuki. At its sheer power, gasps of awe leaked from the spectator stands.
"Hoh... I like you. Fine! Show me your power!!"
"Yeah! Here I come, Thunder God Thor!!"
Their auras swirled into a vortex, and unable to bear it any longer, Heimdall blew the starting whistle.
"Uooooooohhh!!"
Their fists collided head-on. The shockwave sent the barrier—supposedly reinforced many times over—shuddering violently, and the spectators erupted into chaos.
"What monsters. And this barrier was personally erected by that old man Odin..."
The arena's barrier had been cast by Odin himself, its sturdiness beyond question. Hogun couldn't help but marvel at the power of two men who could shake it to its core.
'But this is still just a warm-up... After all, Kazuki-san hasn't even become Guyver yet, and Thor hasn't drawn his prized trump card either...'
Anticipating the battle's inevitable escalation, Rossweisse swallowed hard, alone. And just as she predicted, the real fight was only beginning from here.