While they wait for the distillation to finish to finish the group try and find things to keep themselves occupied, Solaire seems to be reminiscing with Eingyi about the age of gods and fire, they seem to hold fond memories of the people and prosperous age. Eingyi also mentions that he used to be a famous pyromancer, capable of the strongest spells known. Looking at him now, Reima thinks it's a waste that he'd let himself be infested like this, the egg sack on his back completely inhibiting all his actions.
Reima "Eingyi, why do you choose to continue being infested by eggs? You hold the egg Vermifuge do you not?"
Eingyi "I choose to suffer with our fair lady... I'm sure she'd be happy that we'd remained at her side throughout the centuries."
Reima "Wouldn't it be better for you to protect her instead? Forgive me but your not in the most combat worthy state..."
Eingyi "With the mistress guarding the entrance the lady is safe, anyone managing to defeat her wouldn't struggle with me." He seems determined to remain as he is... Maybe once Quelaag's sister can speak again she can talk some sense into them.
The time spent waiting wasn't just him idling around though, Quelaag offered to teach him how to cast basic Pyromancies. She showed him how to manipulate the flame without rendering yourself ash in the process, Reima wanted to upgrade his flame as quickly as possible but when he asked her she outright refused.
Quelaag "You aren't ready to handle such a strong flame... You wouldn't last a day before it consumed you." She was right, Reima found it rather difficult to make the flame do what he wants, it was only after a day of learning that he learned his methods were outright wrong.
Quelaag stated that controlling the flame is a fickle dream and almost impossible, the most powerful pyromancers understand this and prod, provoke and encourage instead. After experimenting a bit Reima found it much easier to handle the flame after this piece of advice. Instead of sorcery which is akin to wielding a sword and swinging it with control and discipline, pyromancy is more like flying a kite and gently pulling it in a certain direction. She tells him of how she herself lays a trail of Mana that the flame follows to form shapes, Reima finds this an ingenious way of countering the flames chaotic nature.
So instead of before where Reima was trying to shape the flame itself, he carefully controls concentrated Mana in the air to make a shape... He has it take a square shape above his hand, the points on each side are a little dull but it's amazing progress as Quelaag has stated many times as she watches him train and discover more ways to utilise the fire for himself.
On the second day Eingyi was teaching Reima some basic Pyromancies while Solaire battled against Quelaag in a game of Gwent, he teaches him he basic fire ball spell and the beginning of fire storm, the radial spell that has fire burst from the ground and incinerate those near. The reason Pyromancy is generally short ranged or thrown projectile is because of the flames instability, extending a Mana trail too far from your person makes it very difficult to control and maintain, the further out it travels the large the amount used. For this reason Pyromancy will never be able to out range sorcery, it's just not feasible to have such fine control over fire, unless you're Lord Gwyn or someone similar.
By the time the distilling process finishes Reima has had his flame upgraded to it's max level, +15 if you use the games numbers. While not spectacularly powerful at using his flame yet, Reima has shown a ridiculous amount of talent for the subject.
Solaire "Sir Ludvig, I think it's been around three days?"
Reima "Maybe? It's kind of difficult to know while in a cave... Let me check."
He walks over and checks the process and finds it completed, he calls the others over as he shows the the vials. One holds the regular blood from the fair ladies human half, and the other is the spider blood. The human blood looks relatively normal except when Reima looks closer the cells seem to be constantly shifting and adapting... This kind of thing is ridiculous, the rate the the cells are dividing reminds him of cancer cells... Something stops them from completely overtaking her body.
He looks at the other vial containing an almost pure black substance, he uses his flame to hold behind it to look closer with the assist of the light. The same thing is also present here, extreme adaptivity to anything presented, it seems to have calmed down from it's initial exposure to pure chaos otherwise the sisters would be fusing with anything they touch.
Quelaag "Well? What is it?" She asks anxiously.
Reima "She should be able to survive having Mutagens introduced. In fact, I fear she might take too well to them."
Quelaag "What does that mean?"
Reima "It means, whatever creature's Mutagen we use on her might have a massive effect on her body structure... Say I use a Giants' DNA, she would probably grow to it's height within a matter of days."
Quelaag "It's fine, as long as you can cure her illness, her form doesn't particularly matter. If she retains her mind and remembers us it's worth it."
Reima sighs "Very well... Now we just have to find a creature that holds extraordinary regenerative abilities... Wait, Solaire remember what you said about the dragon we killed?"
Solaire "Yes, that beast was definitely able to restore itself... It even regrew eyes and severed limbs."
Reima "That's great! We won't have to go looking for one now." The others smile as they can imagine Quelaag's sister recovering soon.
...
Reima "Now... Another three days of waiting... Isn't it just grand..." He says as he remembers that he also has to distil the dragon DNA...
Solaire "Don't mind it, I rather like the company we have at present!" He looks at Eingyi and Quelaag, he didn't seem to mind when he first tried to befriend them, perhaps he's more open minded then other people when it comes to different races?
Hope my explanation on Pyromancy was interesting, I think it's a logical way of thinking about it.
As always, if I missed anything please let me know.