Before anything will happen, I need to know verses and explanations. It was not clear for me the fatwa 8876. I am currently in relation with my aunt. I am 2 years older than her. We are not close to each other before even after college. It was not in my mind that she was my aunt. I got closer to her only when she started to work last 3 years ago and by the months passes by, we had developed to each other more than a relation of a close relatives and beyond. She was my father's sister but only a haft sister since they have different mothers and I don't think she was my paternal aunt in fullest. We are seeking for legality in all aspects. Hoping for positive responses that supports us, is it permissible to marry her?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Even if this woman is not your father's full sister, she is still your paternal aunt since she is your father’s half-sister from the father's side. What you mentioned about you not knowing that she was your paternal aunt or never thought of her like that does not change anything. You must treat her as one of your Mahram women (i.e. female relatives whom you are prohibited to marry).

You already know from the mentioned Fatwa (8876) that the paternal aunt is among the prohibited women for the Muslim man to marry as proved by religious texts and scholarly consensus, and the wisdom behind this prohibition.

If you mean that the relationship between you is of the kind of an emotional relationship in which the man takes the woman as a lover and perhaps lives with her as a couple, then this is a tremendous wrong. It is absolutely forbidden for you to marry her. The punishment for incest in the Islamic law is death. The Prophet, sallallaahu ‘alayhi wa sallam, said: "Whoever has intercourse with a Mahram relative, kill him." [Ahmad and Al-Haakim] Al-Haakim said in his book Al-Mustadrak: "It is an authentic Hadeeth, but Al-Bukhari and Muslim did not report it." Ibn Hajar Al-Haytami commented on this Hadeeth saying: "The gravest kind of adultery ever is incest." [Az-Zawaajir]

Hence, you and this woman must hasten to repent and end any such relationship immediately. Given the circumstance, it is incumbent on you to deal with this woman as you deal with a non-Mahram woman; she should wear the Hijab in your presence and you should not be alone with her since there is a forbidden attraction between you.

Allaah Knows best.