Tasogare no Amrita

In a boarding school where talented young boys are gathered together, Tatsumi has the best grades and is the "president's favorite." However, his place was just stolen by the pretty boy Azuma who's rumored to be getting the president's attention. Tatsumi is irritated by this, but is forced to yield to Azuma whose personality completely changed from the harassment he's been receiving. Ever since then, Tatsumi's been scared of Azuma. Tatsumi ends up in the same room as him but slowly realize where his fear comes from...

(Source: Kadokawa, translated)