Collei

{AN: Sorry for now writting during this month, but I've got a new job and was quite busy, never finding time to it. Let's hope I'm able to write more often now.}

"Will I return to the lab?" Once they found far away and alone, Collei asked Allen.

"Will you return and stay quiet if I promise not to touch Mondstadt and Amber?" Allen asked, making Collei remember her painful days but at the same time these happy days with Amber who trusted her and took care of her, showing her happiness while not minding even facing her own companions as when she saved her from Kaeya.

'If it's for Amber. I will' Collei made a decided look "I-"

"There's no need to answer, Collei" Allen cut her "I was only testing you to make it quicker. I have no intention of sending you with Dottore."

"Why? Didn't you catch me for that?" Collei asked confused.

"Who do you think I am?" Allen glared at Collei, causing her to flinch "You are at most something interesting for him, but not worth enough to personally move to take it. What would I gain for him? A little favor? I have no need for such a pity. I am Columbina, a Harbinger myself."

"If it's not about Dottore, what do you want from me?" Collei asked a little scared

"It's simple. I have curiosity in you, your constitution and your potential." Allen stated.

"You want to use my black fire" Collei glared at Allen, perfectly knowing the dangers behind it, easily being swallowed by it.

Allen smiled at her glare "Eleazar" Allen stated shocking Collei "An illness unique to Sumeru. A manifestation of withering over the human body, causing dark, hard scales to grow over the body, with numbness in the affected area causing clumsiness. As it advances, it will produce fatigue and nerve damage, ending in not being able to control the body and finally falling into a coma before death. That's your illness. An illness which symptoms you did not experience in the last years due to the black fire."

"How do you know?" Collei asked shocked but quickly returned to her glaring 'Of course, she must have known for the Dottore.'

"Collei, sometimes the worst things can become benedictions," Allen said seriously "You had endured much pain for the black fire but thanks to it you were partially cured from the Eleazar. If you were to seal your black fire, the illness will return."

"So I really don't have any future" Collei said with a sad tone, realizing the truth, to be devoured by the black fire or fall for her illness.

"Collei, I will give you two options now" Allen stated "I can set you free and let you do whatever you want with your remaining life or you can join me and work under me" Allen offered.

"Do you want me to work for you?" Collei asked with distrust. "I rather die than work for the Fatui!"

"Of course, you do not have a good opinion of us. But let me tell you that we are not too cooperating with each other, there being quite the bad blood between some Harbingers" Allen explained "I really hate Dottore and his way to act, all to appease his own curiosity without minding anything at all." In his list of most hated Harbingers, Dottore was on the top, wanting to use Ellen for his own experiments.

"If you were to join me, I will give you the opportunity to obtain your revenge as in the end, wouldn't be near him, be the best to obtain information to kill him?" Allen offered "I won't stop there. I will give you power and strength, letting you grow under my protection. On the other hand, if you opt to leave, I won't move an inch for you and your problems will continue. I really doubt that Dottore would make his move, but I'm not so sure about his underlings wanting to win his favor. Who knows the damage that they could cause?"

Listening to her, Collei flinched as memories reflashed about her mother, how she was taken care of and killed when she tried to meet Collei again after sending her with the false oracle to cure her illness. Followed by the painful memories of her experiments.

"You might have gained some friend but would the Favonius Knights be able to protect you? Would you let them put themselves in that danger?"

Collei's expression darkened, remembering their fight against Barnabas with Amber being injured while protecting her.

"You are no different than this curse. Offering me power and strength in exchange of my life" Collei glared at Allen again. Yes, that sweet and sinister voice inside her heart that tried to take control with promise of power.

"I might be similar, that's true. But I won't go against your own happiness. Revenge is a good way to grow strong and fight, but if you truly want to be strong, you will need a reason to live or you will end void of everything. I'll respect both, your revenge and dear ones, helping you achieve your dreams."

"Moreover, do you not remember who saved you before when you were about to be swallowed by the black fire" Collei knew what she was talking about. When she was facing Barnabas, she couldn't control herself, but after Columbina appeared her mind cleared, becoming her again.

"I can help you control it. So rather than seal it, make use of it, make it part of you and use it to cure your illness and to obtain strength."

"You can really help me?" Collei asked unsurely, doubts starting to appear in her mind.

"Yes, I'll make sure of it. You lacked strength, I can give it to you. Revenge, friendship, whatever you want are for you to take." Allen offered her hand to Collei "There's only one question. Will you dare to accept this cursed blessing?"

'Would she help me?' Collei looked at her hand thinking about all the pain that she had suffered, the promise of never asking for help that was broken when she met Amber. She wanted to be someone like her that could help others with a smile, but at the same time, she wanted revenge. To pay Dottore and his men for all the pain that caused her. 'Yes, in the end. I am not like Amber. I can't follow her path.

"I'll follow you" Collei took Allen's hand "But I won't trust you and if I were to discover you have anything to do with Dottore and his experiments, or if you hurt Amber. I'll take my revenge."

"You can try it" Allen smiled "Now, sat down and calm down" Collei sat down and Allen approached at her back "It could be a little painful, but nothing that you haven't experienced before."

Allen drew two short swords previously prepared from her hip. "Fight or you will be swallowed by it." Allen whispered as she started swiftly slashing over Collei's body.

Her swordsmanship was quite unusual, having a strange form in them, changing the profundity, and somehow affecting the inside of the body. This was precisely Skirk's technique, and the movements were exactly the same as she did to Ajax.

'I really doubt that Skirk thought it possible for me to copy her, she being unaware of my talent' Allen smirked 'Would have she liked that I am using it?'

At that time over the Abyss, Allen was able to see Skirk's technique and was able to devour it, even adapting its form to another human like Collei not being a problem at all thanks to her progression as Columbina, now far stronger and skilled than at that time.

"AHHHHH!" Collei growled as black fire surged from her body, the black serpent condensing over her.

'I knew it' Allen grinned 'Collei's condition is similar to Ajax. Her body is highly compatible with the residue of the Abyss and that's the reason she was able to survive all those experiments when others died in them.'

Allen continued with her swordplay, creating the circuits and preparing Collei's body to will the corrupted power of the black fire, the black serpent slowly fusing with her body.

'Kill! Power! Revenge! Hatred!' Collei could hear the familiar voice of the black fire, whispering her to hate and power, trying to corrupt her.

'Fight or you will be swallowed by it' Collei remembered Allen's words. Yes, now was different, she felt stronger than ever, capable of truly fighting it 'NO! I WON'T FALL FOR YOU! YOU WILL BECOME MY OWN POWER!'

All the black fire disappeared as Allen finished her work, sheathing her swords and breathing exhausted of the unusual technique, power and concentration.

"How do you feel?" Allen asked.

Collei stood up and looked at her body in wonder, not feeling as her own. "I feel great" It was the first time that she could remember not having any pain, her body moving as she desired.

*Fush* Black fire surged all around her, burning all her bandages away, being able to perfectly control the black fire without any backslash or voice over it as if it was her own power.

'I really had my doubts of it working, not really minding killing her. But I'm glad that it worked. I have gained a new pawn.' Allen thought looking at Collei with a smile.

"What do you want me to do?" Collei turned over Allen.

"You have something to do before anything" Allen stated "You are now able to will that power, but you are not stronger than before, simply safer. I want you to become stronger that's why I'll send you to the Abyss."

"The Abyss."

"There, your potential will boom" 'Yes, exactly as Ajax. She would be able to absorb the Abyss element further increasing her body strength' "I'll teach you how to cultivate there and grow stronger."

"I understand" Collei nodded, her distrust towards Allen having been lowered by a great deal. "How much time will I be there?"

"Time is chaotic there so who knows? It could be days, months or years." Allen answered.

"Can I write a letter to Amber saying goodbye before going?" Collei asked.

"If you want, you can do it in person. You will work for me, but you are not my slave or anything. You are free to live your own life"

"I'm not ready yet" Collei shook her head "Once I'm truly strong and have grown, that's when I'll meet her again."

"As you wish" Allen helped Collei writing the letter, she barely being able to write due to spending all her life as a lab rat. In the letter Collei said goodbye and told that she will fine, promising Amber to meet again in the future. Collei also prepared some badly repaired clothes which Amber let her wear and Collei stitched them after being cut.

"Please give them to Amber"

The next day, Collei left Mondstadt guided by some Fatui agents commanded by Allen, going over Dornman Port where she will be shipped toward Snezhanaya to enter the Abyss while Allen gave the letter to another agent for him to send at Mondstadt.

'Now Columbina has left Mondstadt, her protection leaving and the wariness of the Knight of Favonius lowered with it' Allen decided, withdrawing her Delusion and returning to Mondstadt as his male self.

'Would Collei be aware of me having everything prepared just in time and all of this being my plan?' Alle wondered 'Also, how would Amber react to the letter? Will she trust to meet her friend again or will she think that it was a lie, with Collei being forced to write it before her own death by the Fatui.' Allen smiled "I'm quite curious."