Bismillah.

Salam alaikum, let me first introduce this shia scholar to dear reader. Nothing but a quote from shia site (quoted from ahlulbaytportal):

Abu-Nadhr, Muhammad son of Mas’ood son of Muhammad Ayāshi Samarqandi Kufi, popularly known as Ayāshi, was an upright Islamic Scholar and an outstanding Shiite Jurisprudent.

Ayāshi was a contemporary and mentor of Thiqatul-IslamKulayni. He was erudite in Islamic Jurisprudence (known as Fiqh) as well as in other Islamic branches of science, literature,Hadith (Traditions/Sayings of the Holy Prophet & his Infallible Household a.s.), and Tafseer (interpretation of the Holy Koran).

So let us see what this prominent shia scholar said in his commentary of Quran.

1) Quran was tampered.

Ayashi wrote in his book (1/25):

Translation:

From Abu Abdullah (alaihi salam): If Quran would be read as it was revealed you will find names in it.

2) Umar was satan.

Ayashi wrote (2/240):

Translation:

From Abu Jafar which said about words of Allah “And Satan will say when the matter has been concluded” – that is second (Umar). AND EVERYTHING IN QURAN WHERE MENTIONED “SAID SATAN” MEAN THE SECOND (UMAR)..

3) Abu Bakr was immorality, Umar bad conduct and Usman was oppression.

Allah said in the Quran (16:90):

Indeed, Allah orders justice and good conduct and giving to relatives and forbids immorality and bad conduct and oppression. He admonishes you that perhaps you will be reminded.

Mal’oon Ayashi in his commentary (2/289) wrote:

Translation:

From Abu Jafar which said regarding this aya – Justice is testimony of La Ilaha illa Llah.  Good conduct means Wilayah of commander of faithful. Immorality is first one and bad conduct is second one, and oppression is third one.