Goddess sisters of DXD

Explanation

Rias POV

I was with Sona, Akeno and Tsubaki in student council room and play chess as i losing I see red magic circle glow as from him step my rook Koneko.

Me : Hello Koneko.I said with smile.

Koneko : Hello president and "look at sona" Sona sempai, i come give report,fallen angel do step and kill Issei Hyoudou A.K.A Pervert and he is diyngright now.

Me : Oh really i must go "stad up and look at sona " ok sona this game you win but next time i will be the one who give you bad time.

Sona : Of course you do " Think" This is what you sayng always and never win once.

Koneko : wait Sempai there is more.

This confuse me and everyone in room.

Akeno : What do you mean there is more Koneko - chan ?

Koneko : As i was spy on pervert being pierced by light spear i heard voice and see my classmate Murayama,Aika and Katase standing out of bush and probably spy issei all day.Koneko informed me.

Me : And let me guess fallen saw them and kill them "sigh" i feel horrible these tree was great friends-.She  was interupted by Sona.

Sona : And great students.

Me : Yes they dont deserve die yet but-.She was again interupted by Koneko.

Koneko : Well you see sempai they are actually alive and healthy.As Koneko say  that in room was complete silence.

Everyone : WHAT??!!!

Me : What! how is that possible?! she is fallen angel and strong!!Any human would die in encourter with her, or at last have  some serious injuries! or injuries at all!   but  they are healthy?!

Akeno : I dont want to believe that.She say shocked and in awe what she hear.

Koneko : But they dont do anything."Everyone was confused"Some strange woman in armor, with unknow armor was strong enough beat and almost kill  her in one minute.She said as everyone was mouth agape open.

Me(scared) : And that woman"gulp" what she was saying.I asked clearly scared.

Koneko : W-Well.She said unsure and scared (because she remember that scary aura and face she made),that is most interesting thing about all of that.

I and Akeno with Sona and Tsubaki looking at her with Scared looks, I mean on the world dosnt exist human who  could alone take elite fallen angel alone,less than one minute and protect tree humans between all of that. What can be more interesting than that ? 

Unknow to her all in room think the same thing like her.

Koneko : Well Murayama seem like know that woman  and  between fight that woman protect Murayama and said this "cough and repeat".

Koneko (repeat) : How dare you attack one of Leona sama children I kill you !! Or something like that.Said Koneko.

Now everyone was in state of confusion.And think.

Sona POV

Me (Mind): Can be she from some royal family ? How that woman act be Koneko description Murayama must be important person and her mother is even more respected. But again they are not devils. But i also doubt that very strong woman like her will be serve under some pathetic human woman, so only question is  who is her mother and What is she?