G.W.I.: Combat Ability
I Battle Apprentice (B.A.)
II Battle Discipline (B.D.)
III Battle Adept (B.Ad.)
In at the first three ranks, it is expected to know a certain amount to combat spells of different classification in terms of strength. The higher the rank, the more proficient you are and more spells you know. The term 'strength' is very vague at this point, as it mostly depends on how you use your spells.
IV Battle Master (B.M.) - required to cast partially chantless
V Battle Mage (B.Ma.) - All combat spells chantless
There is also a requirement for different kinds of spells mastered and the ability of a wizard is also a big part of deciding the rank.
VI Auror (A) - Good combat power. Able to destoy a large house in seconds
VII Hit Wizard (H.W.) - Start building a real, own combat style, own spells and partially wandless
Note: A manor should be able to destroy a manor is seconds.
VIII Elite Hit Wizard (E.H.W.) – Own combat style, own spells, mostly wandless
Note: An Elite Hit Wizard should also be able to destroy a village in a short amount of time, depending on the specialization.
A few known Elite Hit Wizards as example: Pr. Krieg, Auror Moody (Br.), Pr. Flitwick (Br.), Lord Sayre (U.S.)
IX War Wizard (W.W.) - Fullfil special requirement
A War Wizard can cast spells whose requirements would be too much for any other wizard.
Note: Able to destroy a village with one spell
Currently known War Wizards: Albus Dumbledore (Br.), Red Assassin (Jp.), Steven Star (U.S.), Master Yu (Ch.), Louise Delacour (Fr.), Sergei Dolohov (Ru.)
X High War Wizard (H.W.W.) - Can inflict a whole city
Formerly: Albus Dumbledore, Gellert Grindelwald, Voldemort
XI Grand Wizard (G.W.) - Strength not known
Formerly: Probably Merlin, Helga Hufflepuff, Herpo the Foul, Solomon
Note: Nothing is known on how to rise above the strength of E.H.W., rumors hint to the involvement of runes.
Important note: Rank I – VII do not define strength but are decided by the skills a wizard possesses. But in most cases, a wizard would be able to back his 'combat magic rank' with real combat skill. A B.A. could still be able to wipe the floor with a B.Ma. if the gap in experience is big enough or it the B.A. fully mastered a spell.
The difference between reality and actual skill can be large!