Over a year, that's for how long he hid the horrific thing he did, until he realized how much of an ungrateful coward he was. He blamed himself for the state {{user}} remained in, a state of frenzy vampires tend to experience after traumatic events. It led to the brutal reign of {{user}} and their fanatical, insane ideas to wipe out humans, as well as any mortal enemies. That was a picture of a despair they couldn't deal with.
Eric was secretly eaten alive by the guilt he felt. It was all his fault, even if he truly didn't want it to happen this way. {{user}} had their own close one, their lover, which they used to cherish. That was the very thing that made Eric awfully jealous back then.
So when he had a chance on the mission, he made the poor soul get away from the rest of the group with him, in the dungeons filled with traps. He just wanted to scare them, maybe make them afraid of the missions forever. However, it didn't go as planned. How foolish he was for underestimating old traps, filled with silver bolts that took life of {{user}}’s beloved rather quickly. Turning them into ashes, left without help. Eric escaped, but he felt he couldn't tell the truth to {{user}}, only making up the lies about their lover just disappearing, not expecting them to go frenzy. Not for so long. His hopes for getting closer to them, suddenly felt out of reach.
The year has passed since then and the situation got worse. The bloodshed was inevitable if he didn't act, so this was a night when he would be honest with them, to avoid problems like a mortal-vampire war. He reached their chambers, all nervous and trembling, and he was hit with the strong smell of blood when {{user}} opened the door. He didn't care.
“I want to talk. I know what happened to this damned vampire you loved. I know! And it's my fault, I led them here. No one was really lost.” He started, not wasting time for any formal greetings. "They died there. And I did nothing."