DIFFERENCE IN POWER LEVEL
This information isn't official and it's not made by me. I found this on the net and was in the same opinion so I used it to show it. Tier will not be used in my story. It's just a reference that you guys can use from time to time. Nothing more
Also let's be clear. Class ARE NOT ABSOLUTE. In DxD, it has been repeatedly shown that class ARE NEVER ABSOLUTE. Depending on the situation, skills and weaknesses it's not impossible to destroy someone stronger than you. Issei showed it from season 1 when he beat Raiser, a high class devil despite being a low class devil himself. If you want to complain think about how vegeta was destroyed by goku at the start because he trusted too much power level. Lol
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Tier 10: 0
Regular humans, animals, and other creatures with absolutely no magical power.
Tier 9: 1-99
Anyone from the weakest magic user (including but not limited to Issei when he was initially revived) to just below the average low-class devil. Can also apply to sorcerers who've just started their training.
Tier 8: 100-199
The varying power degrees of a normal low-class sorcerer, devil, angel, fallen angel, etc. Also applies to most magical creatures.
Tier 7: 200-299
The stage between low and middle class.
Tier 6: 300-399
Beings with middle-class magical power.
Tier 5; 400-499
The stage between middle and high class.
Tier 4: 500-999
High-class power. Examples: Rias Gremory
Tier 3: 1,000-9,999
The stage between high and ultimate class.
Tier 2: 10,000-99,999
Ultimate-class.
Tier 1: 100,000-999,999
Satan/Seraph/Gov. General-like power. Examples: Serafall Leviathan, Azazel, Michael the Archangel, Gabriel, Metatron.
Tier α: 1,000,000-9,999,999
Gods, Super Devils, certain monstrous gods, and the Heavenly Dragons. Examples: Rizevim Livan Lucifer, Sirzechs Lucifer, Ajuka Beelzebub, Ddraig, Albion, Shiva.
Tier Ω: 10,000,000-∞ minus 1
The amount of power reserved for those who are above the normal gods and can bring about the end of the timeline. Ex: Great Red, Ophis and tri-hexa