[2021] [Lore Question] Zaros vs Tumeken

So there was a point in time where the desert was a lush green forested area, and Tumeken and the Menaphites fought against the Zarosian forces.

During this fight Tumeken unleashed a blast that turned the desert into what it is now, wiping out most of the Zarosian forces with it.

My question is, how was it possible for a tier 5 (inexperienced god) diety to cause something like that to happen? We've only ever seen destruction of that scale before with the Wilderness, and that was done using an elder artefact. How could a god supposedly much less powerful than any one the ones we know now have the power to terraform the entire desert area into what it is now?