A dude with major negativity problems

That would be Jeremiah. The ostensible author is largely contemporaneous with the ostensible Isaiah, and has a similar message: Judah is doomed because the people have fallen away from the proper worship of Yahweh. The work purports to begin during the reign of King Josiah, who was considered a good king and made reforms, but it wasn't enough and, as we know, Judah eventually fell to the Babylonian empire in 587 BCE. Jeremiah purports to begin the book in 609 BCE.

 

However, although it is likely that some of the material originated during that time, and probably was even written by a guy named Jeremiah, the book as a whole was extensively added to during and probably after the Babylonian exile, by the same group called the Deuteronomists who produced the extant versions of Deuteronomy and Judges through Kings. This must have continued after the fourth century BCE because the Masoretic and Septuagint versions are very different -- the Masoretic is longer by some 15%, and the arrangement of the material is different. Jeremiah makes God out to be a very repulsive character, viciously angry and vengeful. As with Isaiah, we won't need to read the whole thing, but we'll get the flavor of it. Here is the first chapter. Since this is the NIV, it's based on the Masoretic text.

One final comment. That God says "Before I formed you in the womb I knew you" is cited by anti-abortionists to suggest that the "soul" exists before conception and is somehow implanted in the embryo. They cite this passage because it is literally the only one they've got in the entire Bible that could possibly suggest any such thing. However, this is obviously about this one, specific individual only. He is claiming to have been specially created to be God's messenger. Of course he is actually psychotic.

 

1 The words of Jeremiah son of Hilkiah, one of the priests at Anathoth in the territory of Benjamin. ² The word of the Lord came to him in the thirteenth year of the reign of Josiah son of Amon king of Judah, ³ and through the reign of Jehoiakim son of Josiah king of Judah, down to the fifth month of the eleventh year of Zedekiah son of Josiah king of Judah, when the people of Jerusalem went into exile.

The Call of Jeremiah

⁴ The word of the Lord came to me, saying,

⁵ “Before I formed you in the womb I knew^[a] you,
    before you were born I set you apart;
    I appointed you as a prophet to the nations.”

⁶ “Alas, Sovereign Lord,” I said, “I do not know how to speak; I am too young.”

⁷ But the Lord said to me, “Do not say, ‘I am too young.’ You must go to everyone I send you to and say whatever I command you. ⁸ Do not be afraid of them, for I am with you and will rescue you,” declares the Lord.

⁹ Then the Lord reached out his hand and touched my mouth and said to me, “I have put my words in your mouth. ¹⁰ See, today I appoint you over nations and kingdoms to uproot and tear down, to destroy and overthrow, to build and to plant.”

¹¹ The word of the Lord came to me: “What do you see, Jeremiah?”

“I see the branch of an almond tree,” I replied.

¹² The Lord said to me, “You have seen correctly, for I am watching^[b] to see that my word is fulfilled.”

¹³ The word of the Lord came to me again: “What do you see?”

“I see a pot that is boiling,” I answered. “It is tilting toward us from the north.”

¹⁴ The Lord said to me, “From the north disaster will be poured out on all who live in the land. ¹⁵ I am about to summon all the peoples of the northern kingdoms,” declares the Lord.

“Their kings will come and set up their thrones
    in the entrance of the gates of Jerusalem;
they will come against all her surrounding walls
    and against all the towns of Judah.
¹⁶ I will pronounce my judgments on my people
    because of their wickedness in forsaking me,
in burning incense to other gods
    and in worshiping what their hands have made.

¹⁷ “Get yourself ready! Stand up and say to them whatever I command you. Do not be terrified by them, or I will terrify you before them. ¹⁸ Today I have made you a fortified city, an iron pillar and a bronze wall to stand against the whole land—against the kings of Judah, its officials, its priests and the people of the land. ¹⁹ They will fight against you but will not overcome you, for I am with you and will rescue you,” declares the Lord.

Footnotes

1. Jeremiah 1:5 Or chose
2. Jeremiah 1:12 The Hebrew for watching sounds like the Hebrew for almond tree.