Ranking and Grading

In the Tower weapons, Inventory-Items, Wands, Pockets, Lighthouses, Mobiles and even the different kind of skills mastered by Rankers and Regulars are all given ranks according to their level.

Both Rank and Grade are used in this relation and bear the same meaning.

We do not yet know who or how these ranks are given. But it is safe to assume that a ranker's or in specific a regular's ranking will change as he/she gain strenght and obtain more skills.

The Levels of Ranks
The ranking system goes from SS+ as the highest and down to F10 as the lowest. The scaling goes as following:

SS+ > S+ > S1 - S10 > A1 - A10 > B1 - B10 > C1 - C10 > D1 - D10 > E1 - E10 > F1 - F10

Known Examples of Ranked Skills of Rankers and Regulars:
Just a few:

Rankers:
Notice that Yu Han Sung turned down the position of High-Ranker, from this we can make the assumption that overall score of 8A is enough to become a High-Ranker.
 * Yu Han Sung overall 8A
 * Yu Han Sung Intelligence 2A
 * Yu Han Sung Shinsoo Control 7A
 * Yu Han Sung Shinsoo Resistance 4C
 * Yu Han Sung Physical Ability 8E
 * Lero-Ro overall 10B
 * Lo Po Bia Ren overall 10B
 * Quant overall 5C

Regulars:
Note that all regulars who pass the tests on the 20th Floor automatically become E-Ranked.
 * Androssi Zahard overall 6E (in Part 1 )
 * Anak Zahard overall 10E (in Part 1 )
 * Koon Agero Agnis overall 3F (in Part 1)
 * Phonsekal Laure overall 5F (in Part 1 )
 * Hatsu overall 7F (in Part 1 )
 * Rak Wraithraiser overall 7F (in Part 1 )
 * Hong Chunhwa overall 7F (in Part 1)
 * Ship Leesoo overall 8F (in Part 1 )
 * Sunwoo Nare overall 9F (in Part 1)
 * Parakewl overall 10F (in Part 1)

Known Examples of Ranked Weapons and Other Items:
A-Ranked weapons and items are extremely rare, to such an extent that even rankers seldomly own them. And only a High-Ranker can be expected to own more then one. To illustrate just how rare A-Rank Weapons/Items are one may notice that neither Lero-Ro, Lo Po Bia Ren or Quant own a single one.
 * White Oar the only S+ Rank weapon in the Tower (it is a sword)
 * Golden November a S-Rank weapon (weapon type unknown).
 * Black March a A-Rank Needle ( w hen ignited ).
 * Green April a 7B-Rank Hook (most likely A-Rank when ignited)
 * Narumada a 7D-Rank Sword.

Notes and Trivia
Notice that it seems as if the normal numeric system is not used for S or higher rank weapons. Maybe because there are so few S or higher rank weapons.

Since all regulars recieves an E-Grade pocket when entering the tower, it seem safe to assume that E is the lowest kind of pockets.