Ebrose

"When Robert's Rebellion was raging people thought the end was near; the end of the Targaryen dynasty! How will we survive? When Aegon Targaryen turned his eye westward and flew his dragons to Blackwater Rush - "the end is near, how will we survive?" And thousands of years before that, during the Long Night we could forgive them for thinking it was the end, but it wasn't, none of it was. The Wall has stood through it all, and every winter that ever came has ended."

- Ebrose to Samwell Tarly

Ebrose is an Archmaester of the Citadel, one of the governing members of the Order of Maesters.

Biography
At some point early in his life, Ebrose committed himself to the life of a maester, and would have studied at the Citadel in order to forge his chain of service. Eventually he rose through the ranks, ultimately achieving the position of Archmaester, making him one of the most senior members of the order.

Season 7
Samwell Tarly assists Ebrose with the dissection of the body of Maester Wayland, weighing the organs in a scale. Samwell repeats his request to access the restricted section of the Citadel's library in order to research the White Walkers, a request which Ebrose denies. While Ebrose assures Samwell that he does believe his claims regarding the Walkers, he explains the reason for his reluctance, and emphasizes that the duty of a maester is to be skeptical.

In the books
In the A Song of Ice and Fire novels, Ebrose is an Archmaester of the Citadel. Each Archmaester bears a ring, rod, and mask forged of a certain metal to designate expertise in a particular field of study. Ebrose's ring, rod, and mask are silver, signifying his mastery of the healing arts. The Citadel is structured someone like a university, by which analogy Ebrose is essentially the head professor of medicine. Some fields of study are more respected than others: study of the "higher mysteries" (Magic) is thought of as lowly and trivial, but the archmaester of medicine is very highly respected, as it is one of the core duties of maesters.

As an Archmaester, Ebrose sits on the Conclave - the ruling body of the Order of Maesters, and is responsible for electing the Grandmaester to the king's Small Council.

Acolytes training to become maesters must study under Ebrose in order to earn a link of silver for their chains. He is regarded as a patient and kindly tutor, but is known to become exasperated when dealing with the persistent failures of an unpromising student. One such pupil, named Pate, once remarked that Ebrose's "weary sighs" were just as hurtful as the outright insults of Archmaester Vaellyn.

Qyburn conducted human experimentation, unethically vivisecting living men to further his medical research: it is explicitly said that one of the things driving him was a desire to surpass even Archmaester Ebrose as a healer. When the maesters (including Ebrose) found out what he was doing, Qyburn they expelled Qyburn from their order.