Yn gremory the first born son of sirzechs and grafiya Yn was happy with his family that all changed when he is known for not having destruction magic or grafiya ice magic so Yn life changed after that as In school the teachers ignored him and the students laughed at him also rias enjoys messing with him for being powerless at home wasn't better either sirzechs and grafiya including his grandparents ignored him as the maids only cared for him as they feed Yn and comfort Yn.

Nine months later Yn was told he was going to be a brother as grafiya just cave birth to millicas but yn didn't care as the family was happy that millicas was born after a few more years millicas and rias discovered they have destruction magic as the family celebrated bringing friends and other high profiled devils.

Yn was just sitting in a chair waiting for this to be over as he was told to be here for the celebration Yn knew his family wanted to do just to mock him as someone was walking to him it was sona

Sona:Yn

Yn:what do you want sona

Sona:your told me to tell you to join the family

Yn:I rather hang myself then go over there

Sona:Yn come on it's rias and millicas celebration

Yn:again I rather hang myself tell them that

Sona:but Yn-

Yn:I said

Yn eye color changed to yellow Yn looks at sona

Yn:go tell them I said that

Sona backs away from Yn

Why Yn eye color changed you asked well after letting out his anger out Yn released his power but it wasn't magic it was a sacred gear it was called sith

Yn learned about its abilities so now Yn has power but Yn kept it to himself as Yn trained his knee power but the more he used it the more he changed

Yn sees sirzechs walking towards him

Sirzechs:Yn sona told me that you rather hang yourself then be here

Yn:yep

Sirzechs:but aren't you happy that your young brother and auntie have destruction magic

Yn:why would I be happy about old man you and your wife never celebrated anything about me so why should I bother being happy with this crap throughout the years of neglect by you two and your parents and being laughed at by rias and the others why should I be happy give me one good reason I should be happy about this

Sirzechs:...

Yn:none exactly you know what I hope you killed and your wife get killed

As the guest gasp of what Yn just said

Sirzechs:you wants to die

Yn:yes nothing but neglect you and your wife gave but you too give millicas happiness because he has magic not one of you once been there for me because i didn't have destruction magic I can't control that or I didn't get your wife ice magic either so it's both your faults for not giving me the magic I hope me or somebody else kill you I really hope you both die including this so called perfect family

Sirzechs:you want to kill us

Yn:yes i really do but including your parents and your bitch of a sister so be ready because who knows when or where will I kill you hope you have some nice memories that's all you and your family are going to have after I'm done after that I'll kill the ones that laugh and belittle me.

Yn was leaving the room party but sirzechs stops him

Sirzechs:I'm sorry yn but I'm going have to-

Yn interrupted sirzechs as Yn shot force lightning as sirzechs was sent flying

Grafiya:sirzechs Yn stop this nonsense right-

Grafiya stops talking as she felt someone choking her as she was Lyft in the air as she looks down to see Yn choking her

Yn:I'll make sure your death is most painful grafiya

Yn release her as Yn lefts the party as the guest we're shocked Yn has power as Yn heads towards his room and got his stuff in put it in a duffel bag and leaves the gremory mansion

Few hours later

Sirzechs and grafiya were in there room after the party had to end

Grafiya:Yn

Sirzechs:he's changed because of us now he wants us dead by his own hands

Grafiya:but how did he get that power from

Sirzechs:maybe he's anger released his power but we didn't notice it

Grafiya:can we find a way to change his mind

Sirzechs:no I see it in his eyes Yn wants us dead when sona told me Yn eye color changed I knew Yn wants us to kill us

Grafiya:he's going to hurt millicas

Sirzechs:he wouldn't kill millicas so quickly he wants us to suffer first

Grafiya:what do we do

Sirzechs:alert other high devils if they see yn tell them to capture him so we can see his memory on how he got his power

Grafiya nods

Grafiya:Yn I'm sorry

Yn pov

Yn finally left the devil faction and was at the human world but in Kyoto as yn see a girl his age

???:excuse me sir who are and why are you in my faction

Yn:sorry I was escaping the devil faction I couldn't handle my family didn't care about me

???:sorry to here that you seemed tired would you like a place to stay

Yn:yes please

???:then follow me

Yn follows the woman

Yn:never got your name

???:my name is

Yasaka
(Imagine she a bit younger)

Yasaka:what your name

Yn:Yn gremory but since I left the family call me Yn ln