This is mostly a port of this thread I have made a few times before.
The Marvel Power Rankings used commonly in the vs communities has caused some problems with their ambiguities as to what exact level of power is what level. I also do not like the VS wiki tier system which I find to be fallacious in it's reasoning near the top. However I don't like to complain without offering a solution. As such I wished to humbly present the Tier System I use and which I think works best for our form of debating.
This is highely systemized as you may notice. It should be noted that a great many Death Battles occur entirely within Tier 14. And the Vast Majority take place between Tiers 15 and 12. However it is the Tiers beyond 12 where this system becomes most important to avoid stomps.
Mortal Super-Tier:
Tier 16: Low Mortal/Gradual Local Threat: Can affect and gradually threaten the local area. Below Peak Human. Having any combat training or experience is rare. Death Battle examples include Justin Bieber and Rebecca Black.
Tier 15: Mid Mortal/Immediate Local Threat: Can immediately threaten everything in their surroundings. Peak Humans or Lower Level Superhumans. Can generally be defeated by a single well-equipped human in real life. Many are fast to achieve to superhuman speeds, even becoming blurry to the human eye. Having Ranged Attacks at this tier is very important. Death Battle examples include Mr. Satan, Dan Hibiki, Koopa, and Goomba. May also include Batman and Captain America...however they can also be argued to be Tier 14.
Tier 14: High Mortal/Gradual City Threat: Can damage signfiigant parts of a city, ranging from small buildings to multiple city blocks. Can gradually threaten and potentially affect all of a city. Often powerful enough to take on large groups like squads or entire armies. Many are fast enough to become invisible to the human eye, and some are fast enough to go supersonic or enter missile-like speeds. Flight is a signifigant advantage at this stage. Most Death Battle Combatants are at this level.
Tier 13: Top Mortal/Immediate City Threat/Sub-Demigod: Immediate threat to an entire city. Comparable to a Nucleur Weapon. Likely fast enough to travel around the planet personally, and most can break the escape velocity. Often has abiltiies that allow them to manipulate the battlefield. Has the capacity to single-handedly conquer civilizations like Modern Earth. Death Battle Combatants at this level include Gaara, Sonic, Shadow, Knuckles, Tails, Mario, Luigi, Charizard (And Mega Charizard), Greymon and Metal Greymon, Gamera, and probably some more I am forgetting.
Demigod Super-Tier:
Tier 12: Low Demigod/Gradual Planetary Threat: Can affect all of and gradually threaten a planet...can destroy islands, countries or continents and can potentially lifewipe the Earth with attacks. Can generally destroy large-ish asteroids. Likely fast enough to travel to nearby planets and easily travel around the planet. Often has extreme survivability such as regen or the ability to survive extreme conditions such as heat, cold, acids, and the vacuum of space. Death Battle Combatants at this level include Wargreymon, Arguablly Mega Charized at Max, Akuma, Kratos, Iron Man, Most of Link's strongest stuff and Epyon.
Tier 11: Mid Demigod/Immediate Planetary Threat: Immediate threat to a small planet like the Earth. Likely Fast enough to travel around the Star System. Often has dangerous abilities that can be avoided such as energy manipulation or matter manipulation. Death Battle Combatants at this level include He-Man, Astro Boy, Super Sonic, Super Shadow, Kirby, Raiden (Unrestricted), Shao Khan (Unrestricted), and Base Doctor Doom
Tier 10: High Demigod/Gradual Stellar Threat: Can affect all and gradually threaten a Star System. Can casually destroy a small planet and can destroy large planets or small stars. Can destroy anything in a Star System out of potentially the Star. Likely fast enough to easily travel around the Star System and fly into other star systems. Oten have dangerous abilities that are hard to avoid like mind or soul manipulaton. Death Battle Combatants at this level include Classic Mega Man and Peak Samus Aran
Tier 9: Top Demigod/Immediate Stellar Threat/Sub-Ascended: Immediate threat to a Star System. Likely fast enough to travel around an entire galaxy. Often has dangerous abilites that affect a large area like spacetime manipulation. Death Battle Combatants at this level include: SSJ2 Vegeta (Composite), Cloud, Tifa, and Sol Badguy
Ascended Super-Tier:
Tier 8: Low Ascended/Gradual Galactic Threat: Can affect all of and gradually threaten all of a galaxy. Likely is fast enough to easily travel around the galaxy or even fly into other galaxies. Often has abilities like reality-warping and affecting other planes of reality. Death Battle Combatants at this level include: Superman, Wonder Woman, Lex Luthor, Goku (SSJ3 as well as GT Goku in general), SSJ4 Vegeta, Composite Buu, and Thor (616)
Tier 7: Mid Ascended/Immediate Galactic Threat: Immediate threat to a single large galaxy. Likely Fast enough to travel around the universe. Often has abilities like dimensional manipulation and existence destruction. So far no Death Battle Combatant has been at this level exactly.
Tier 6: High Ascended/Gradual Universal Threat: Can affect all of and gradually threaten all of a single universe. Likely is fast enough to go to any point in the universe or even into other universe. Often has abilities like causality manipulation and the some degree of increased awareness about the universe or the ability to create life itself. Death Battle Combatants at this level include Goku (God Forms), Vegeta (If he went into his God Forms), and Chuck Norris. Pre-Crisis Superman was also generally at this level...although there are a few showing suggesting even higher power.
Tier 5: Top Ascended/Immediate Universal Threat/Sub-Super-Cosmic: Immediate threat to a universe. Affecting the first cardinal of infinity. At this level speed starts to not matter. Often has abilities like abstract concept manipulation and quantum manipulation. Deah Battle Combatants at this level include White Bomber and Wonder Woman (Godwave)
Super-Cosmic Super-Tier:
Tier 4: Low Super-Cosmic/Gradual Multiversal Threat: Can affect all of and gradually threaten an entire multiverse. Between the first and second ordinals of infinity and can affect multiple universes at once. Can usually casually destroy a universe. Often ha some level of spacetime transcendence. The only Death Battle Combatant that has appeared at this level before is Sun-Dipped Superman. Nothing shown on Death Battle has gone higher and admittigly Super-Cosmic beings are hard to depict. Hell, even Ascended beings are hard to depict. That said I have faith that if Death Battle wanted they could go higher.
Tier 3: Mid Super-Cosmic/Immediate Multiversal Threat: Immediate threat to all of a multiverse. The second cardinal of infinity. Often has abilities like abstract existence or nigh-omniscience. Galactus vs. Unicron have been confirmed for a future Death Battle and Galactus's Normal Peak is at this level.
Tier 2: High Super-Cosmic/Gradual Omniversal Threat: Can affect all of and gradually threaten the omniverse. Between the Second and Infinite Cardinal of Infinity. Often has a metafictional component to their powers. Unicron is here as well as Galactus with the Ultimate Nullifier. Superman Prime 1,000,000 (Which DB described as "Pretty much God") is here as well.
Tier 1: Top Super-Cosmic/Immediate Omniversal Threat: Immediate threat to an omniverse. The Infinite Cardinal of Infinity. The REAL big boys... I am only personally familiar with Marvel and DC Characters that reach this benchmark although I heard both the Lovecraft Mythos and Dark Tower have done so as well. I must confess, I find it doubtful DB will ever do a match-up with characters from this tier.