Yahweh was a national god. After the life of Jesus, he was conflated with the universal God:

Yahweh[a] was an ancient Levantine deity, and national god of the Israelite kingdoms of Israel and Judah.[4] Though no consensus exists regarding the deity's origins,[5] scholars generally contend that Yahweh is associated with Seir, Edom, Paran and Teman,[6] and later with Canaan. The origins of his worship reach at least to the early Iron Age, and likely to the Late Bronze Age, if not somewhat earlier.[7]

In the oldest biblical literature, he possesses attributes typically ascribed to weather and war deities, fructifying the land and leading the heavenly army against Israel's enemies.[8] The early Israelites were polytheistic and worshipped Yahweh alongside a variety of Canaanite gods and goddesses, including El, Asherah and Baal.[9]

[wiki for Yahweh]

The term demiurge derives from the Latinized form of the Greek term dēmiourgos, δημιουργός, literally "public or skilled worker".[note 20] This figure is also called "Yaldabaoth",[73] Samael (Aramaic: sæmʻa-ʼel, "blind god"), or "Saklas" (Syriac: sækla, "the foolish one"), who is sometimes ignorant of the superior god, and sometimes opposed to it; thus in the latter case he is correspondingly malevolent. Other names or identifications are Ahriman, El, Satan, and Yahweh.

[wiki for gnosticism]

Atleast, that’s one theory.