As far as Caesar knew, bloodline ratings at Cassel College were adjusted based on students' performance after enrollment.
For instance, while the members of the Board of Trustees did not necessarily possess high bloodline purity, each of them held an "S" rank due to their status and contributions. Similarly, an undergraduate student with a "B" rank who performed exceptionally well on Operations Division missions could be promoted to an "A" rank; such occurrences were quite common.
Then there was that one loser who overstayed his welcome and refused to graduate. Given how utterly atrocious his performance was, Cassel College had specifically created the "E," "F," and even the unprecedented "G" ranks just for him.
Chapter 290