Megalomania is a sinful condition—though potentially sometimes brought on by actual brain damage—in which an individual greatly exaggerates his or her importance. Calling God a megalomaniac is to challenge His character. However, even a cursory review of Scripture shows that God is kind (Titus 3:4-5a), humble in His incarnate state (Philippians 2:8), patient (2 Peter 3:9), and other-focused (Romans 5:8). None of those characteristics align with megalomania.
Because God never lies (Titus 1:2), when He says that He is all-powerful (Luke 1:37), all-knowing (Psalm 147:5), and omnipresent (Psalm 139:7-8), we can take Him at His word. Indeed, those characteristics are perfectly in line with His nature as God.
Those who call His character into question generally do so to provide themselves with an excuse to not obey Him (Romans 1:18-23). However, because God is who He says He is, that is a fool’s errand that ends with being on the receiving end of His eternal, judging wrath.
On the “day of the Lord” (1 Thessalonians 5:2), Jesus will return, and all rebellion will be squelched. Those who are alive today and under that coming wrath are looking for any way to pretend that they will not be held accountable. However, all of creation screams that God demands justice (Romans 1:18-20; Psalm 19:1-6).
Because God is merciful and humble, He has given us the Bible. In it, He has detailed not just His wrath, but the one way to escape it. That is through His Son. His Son did not need to die because only sinners die (Romans 6:23a). However, God’s will was to kill Him to offer us life (Isaiah 53:10a). Despite coming to die, Jesus lived humbly, submitted to the Father’s will. In so doing, He was the perfect example of humility (Philippians 2:8). His humility and kindness compel us to repent of our rebellion (Romans 2:4). All who believe in Jesus as Savior, will be saved when God’s wrath comes (Romans 5:9).
Trying to find flaws in God by calling him names like megalomaniac is dishonest and does nothing to stop His wrath from coming. He is our Creator (Genesis 1) and has complete authority. Rather than see Him as evil and self-centered, praise Him for being humble towards humankind, giving us ample time to be saved.