Hesiod's Theogony gives the earliest surviving account of Typhon's battle with Zeus, but later Greek mythographers, particularly Apollodorus writing centuries afterward, expand the figure considerably, crediting him as the father of a long list of monsters, including Cerberus, the Hydra, the Chimera, and others, in genealogical detail that goes well beyond what Hesiod actually states. This kind of retrospective genealogical building, tying a fearsome late addition to a family tree back to an earlier singular monster to explain where all the era's monsters came from, is a recognisable pattern in how Greek myth was elaborated over time by writers working centuries after the earliest poetic sources.
Separately, Greek travellers and writers visiting Egypt identified Typhon with the Egyptian god Set, a practice called interpretatio graeca in which Greeks mapped foreign deities onto figures from their own mythology based on rough similarity of role, here both being violent, chaos-associated adversary figures. This equation tells us more about how Greeks categorized unfamiliar religions than about any genuine historical connection between the two figures, since Set and Typhon developed independently within entirely separate mythological systems, and the identification was a later interpretive convenience rather than evidence of a shared origin.