An Origin Level is considered a tier of Degree of Assimilation. There are seven tiers, Origin Level 7 to Origin Level 1. Each jump of tier is considered to be an evolution for the transcendent, though if something goes wrong, mutations could occur. The gap between each Origin Level increases the higher up it goes. Especially the difference between the lower four tiers and the upper three tiers. The difference can be considered to be between an infant and an adult.
To use a metaphor, it was like a generator that determined how much power one was able to exert. With sufficient strength, one could do anything. The higher one’s Origin Level was, the more mana one could exert at once.
Origin Levels are not only meant for transcendents but mutated creatures as well. A good example is in Chapter 34 where the bloodhorn deer was described to be Origin Level 3.
These seven tiers are similar to the House Resurgence System's F-tier to S-tier.
At Level 7, the only spells that can be learnt are functional spells that had weak offensive power like for drying clothes or retrieving objects.
Origin Level 6 is the minimum level required to learn any spells with actual offensive power. As Origin Level 6 enhanced their control over their mana, a new array of spells could be learned. Most members of the militia are at Origin Level 6, which means that their strength is roughly comparable to that of a horse or ox. In Chapter 32, it was mentioned that they can curb even lions with ease though mana-mutated demon beasts might still pose a bit of trouble.
Starting from Origin Level 3, transcendents are considered to be high-level. They are considered to have immeasurable power. Origin Level 3 possessors were already the leaders of countries. Even amongst tens of thousands of Origin Level 4 transcendents, none would be able to reach this height. This is because these transcendents lack a belief core, a requirement to reach Origin Level 3. Other than that, all they would require is accumulation of mana.
The mana from an Origin level 2 is so strong that it can shake an entire city. Origin Level 2s are generally chiefs and leaders of militia groups.
Origin Level 1 transcendents are considered to be god incarnate. They can shake cities from a simple "greeting" spell. There have been few Origin Level 1 transcendents revealed so far in the novel, Magician King Priestley Maxwell, Astrid Arde, Antonio Wyatt and Holy emperor John Xeclyde. These two fought each other which resulted in the destruction of half of Leinster.