The Infinity Tower.

For years, society was normal, until one day, a massive black tower fell from the sky, which released several monstrous beings onto the earth, who wreaked havoc upon humanity, as conventional weaponry, such as guns, could not harm them. However, over time, humans adapted, and a select few, roughly 5% of humanity, obtained powerful magical abilities, allowing them to easily push back the monsters back into the tower. In the present day, it is extremely common to see people with these abilities, and people who use these abilities to enter the tower and claim it's treasures are known as 'Hunters'. The first 5% of humanity to gain these abilities are today known as the S-Rank Hunters.

The Infinity Tower is a seemingly infinitely tall black tower that sticks out from the earth, which is divided by 'floors' of varying difficulty, marked by their number. The Infinity tower's entrance is known as Floor 0. Every 6th floor is a 'rest' floor where members of a party can rest and regain some health before heading up to the next floor, and every floor before a rest floor contains a boss which must be slain in order to move on to the next floor. Every second rest floor is a shop which can be used to sell unwanted items for Gold, or buy powerful recovery items and equipment with Gold. Gold is a physical currency unique to the Infinity Tower that consists of small gold coins. Some establishments outside of the Infinity Tower accept Gold as an alternative to cash.

'The System' acts as both an inventory and a form of improvement for Hunters, as it allows them to become stronger and obtain new skills through slaying monsters. And the most efficient way to slay monsters? Climbing The Infinity Tower.

All of humanity has access to The System.

The System also grants users access to Mana, a resource used to cast powerful magic Spells, as well as an 'inventory' that can be used to store and equip objects, often items dropped from enemies in the tower.

Hunters have 6 Ranks: F-Tier. Most Non-Hunters are at this level of power, and F-Tiers usually have the same strength as normal humans, if not lower. D-Tier. Most Hunters start at this level when first registered as Hunters. C-Tier. Most Hunters at this level are strong enough to make a living off of the lower floors of The Infinity Tower. B-Tier. Most B-Tier Hunters are strong enough to stop a full speed car. A-Tier. A-Tier Hunters, although extremely rare due to how long it takes to reach this level of power, and how dangerous The Infinity Tower is, are more than strong enough to lift large Aircraft Carriers with relative ease. S-Tier. S-Tier Hunters are so extremely powerful, that it cannot be categorized further.

Monsters in The Infinity Tower also follow the same Ranking system.

In order to become a Hunter, you must pass a test, where you must fight and kill 3 monsters of a Tier of your choice. If you win, you become a Hunter with the same rank as the Monsters you defeated. For example, if you chose 3 C-Tier monsters and won, you would become a C-Tier Hunter instead of the usual D-Tier.

The System, alongside it's other benefits, also offers 'Classes' to choose from. There are 6 total Classes to choose from, each with different Upsides and Downsides:

1-Knight. Knights are extremely durable, and can dish out some serious damage when in close range, but are slow and next to inept at using magic.

2-Mage. Mages are the polar opposite of Knights, being able to dish out extreme damage at long ranges, but are extremely vulnerable to damage themselves, and have next to no close-range options.

3-Cleric. Clerics are spellcasters that have exclusive access to powerful healing spells, in exchange for being able to do little to no damage to enemies.

4-Paladin. Paladins are the compromise between Clerics, Mages and Knights, having access to healing spells, good close-range and long-range options, and good defense, however, Paladins are jacks of all trades, masters of none, and as such, they are weaker than Clerics, Mages, and Knights in their specific fields.

5-Rogue. Rogues are somewhat of a side-grade to Knights, shunting defenses in exchange for extreme speed and stealth to counterbalance their lack of range.

6-Summoner. Summoners are the most unique of all the classes, as they don't have anything special regarding their stats, but can instead make 'Pacts' with monsters they defeat, which they turn into Summons to use for battle. The power of a Summoner is solely determined by the power of their Summons.

When you level up using The System, your stats improve. There are 5 stats: 1-Strength. Strength improves Physical Damage, and physical strength. 2-Constitution. Constitution improves physical health, Durability, and Debuff resistance. 3-Dexterity. Dexterity improves your Stealth, Speed, and Attack Speed. 4-Intelligence. Intelligence increases your Maximum Mana, Spell Damage, and Mana Regen. 5-Spirit. Spirit improves your Summons, Increases your Max Summons, and reduces the mana cost of spells.

A Hunter's level usually determines their average strength. A minimum 25% Level difference is needed for a fight to be effortless (E.G. A monster is level 100, and a hunter is level 125, the level 125 hunter would be able to effortlessly defeat the level 100 monster).