See also: Death Weapon Meister Academy
Anyone recognized as three-star (三つ星, Mittsu Boshi) are generally among the highest ranking people in Death Weapon Meister Academy's star ranking system within the E.A.T Class. Due to such a high ranking, they're known to be extremely skilled in combat, whether it be with a weapon on hand, bare handed, an unorthodox weapon (i.e tombstone), or a combination of all.
Meisters recognized as such are referred to as three-star meisters (三つ星職人, mittsu boshi shokunin) while weapons are presumably recognized as three-star weapons (三つ星武器, mittsu boshi buki).
Promotion to such a rank is difficult and requires the faculty members of the E.A.T Class to agree before promoting them. However, it is known that anyone who manages to wield the Holy Sword and showcase a strong will of strength may bypass up to the highest ranking no matter their previous standing.
Although the highest ranking and allow to partake in the most dangerous of missions, responsibilities are different and dependent on the individual's occupation; students are still only able to access library materials up to level 2 while instructors can access up to level 3 and finally, select elite meisters and death's weapons can access level 4. Three-star status also allows individuals to partake in "A" rank missions and even presumbably "S" rank, the highest known threat level within the academy.