Sebastian was flabbergasted when he came to terms with the situation that he just found himself in, he discovered that he was already screwed.
When Sebastian first met the soul fragment of the Black tier Leviathon and subsequently read its memories, on not seeing any information about the 2nd test, he already felt that something was suspicious but he didn't expect this.
The euphoria that he felt on completing the first test and getting the rewards evaporated like the wind once the realization of everything settled in his mind.
According to what the unknown voice just said in his head, here, he had no choice for himself, it was either he participated in the inheritance test or he simply lived his lifespan to expiration here and rot to death.
There were no choices here, the choice was already made for him.
