"The Hebrew word for God's justice is not a forensic term."
It is a forensic term in Judaism. From a Jewish encyclopedia:
"The ten days starting with Rosh Hashanah and ending with Yom Kippur are commonly known as the Days of Awe (Yamim Noraim) or the Days of Repentance. This is a time for serious introspection, a time to consider the sins of the previous year and repent before Yom Kippur.
One of the ongoing themes of the Days of Awe is the concept that G-d has "books" that he writes our names in, writing down who will live and who will die, who will have a good life and who will have a bad life, for the next year. These books are written in on Rosh Hashanah, but our actions during the Days of Awe can alter G-d's decree. The actions that change the decree are "teshuvah, tefilah and tzedakah," repentance, prayer, good deeds (usually, charity). These "books" are sealed on Yom Kippur. This concept of writing in books is the source of the common greeting during this time is "May you be inscribed and sealed for a good year." ".
God keeps books and righteousness (tzedakah)can alter the negative writing in the book in order to have a good year. The writing is judgement of the life lived the past year.
Isaiah equates righteousness with judgment, Isa. 28:17, "Judgment also will I lay to the line, and righteousness to the plummet: and the hail shall sweep away the refuge of lies, and the waters shall overflow the hiding place.", but then he goes on to say all of our righteousness is less than worthless, preparing the way for the righteousness that Jesus brings on our behalf by satisfying the righteousness for our sin. Isa. 64:6, "But we are all as an unclean thing, and all our righteousnesses are as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away."
In Talmud and Mishna the popular demonology was accepted by the end of the 3rd century AD.
Your arguments are with Judaism. Read any Jewish sources, modern or ancient, and you will find that Satan has no power of his own but must obtain permission from God. Thus, in Judaism, Satan receives his orders from God.
The concept of devil, prince of demons, etc. being synonymous with Satan is first encountered in "Apocrypha" and from there, through the use of Septuagint as Scripture by the Apostles, it finds its place in the New Testament.