Hunting a dangerous monster was not something that was in Evan's plans, however, Idris actually put a lot of effort into talking him into it.
Evan not only got the chance to test his new weapon in practice but also to get his first artifact for it.
He remembered his fight against Drakar in detail, it was the strongest and most dangerous opponent he had faced since he had been reborn. Barring the demon's strength and powerful spells, Drakar's artifacts had been enough to deal with almost all of his opponents. Only Evan was able to stay in formation, thanks in large part to Hana's cursed eye.
Evan realized that artifacts could be very powerful and valuable equipment in any fight. Without his sword, or the power of demons, he would not be able to reach Nightwell, for the more sources of power he had, the better.