The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
Eru Ilúvatar is a creator deity with omnipotent powers, shaping the entire universe and its fundamental laws in Tolkien's legendarium. Reinhard Heydrich from Dies Irae possesses immense abilities within his own narrative, including reality manipulation and impressive combat skills, but he operates within a more limited context compared to a god-like figure.
In a comparison of sheer power and influence, Eru Ilúvatar would likely be more powerful due to his status as the ultimate creator. Reinhard's abilities are formidable, but they would not match the overarching, cosmic power of a being like Eru.
I couldn't have found a better or more concise or more logical explanation for "why" Eru > Reinhard than the A.I. myself.
A.I. have become pretty good at answering questions like these, they are no longer to be ignored, just my opinion.
First In Tolkien's Lord of the Rings/The Silmarillion narrative about the Music of the Ainur/ Ainulindalë parallel the creation myth. Eru Ilúvatar is the only supreme being creates the Ainur or "Holy Ones" who are his offspring or emanations of his thought/mind, This is parallel to the Neoplatonic idea of Emanationism where the One, the supreme being creates higher beings that emanations of his attribute/part.
it's just that Eru does share similar traits/descriptions to a tier 0 boundless character as described above. in fact tier 0 characters are directly inspired by Neoplatonism. Tier 0 itself is entirely influenced/based on this.
RIP all Hadou Gods.