L15 and no quests to do

[Nekodar]

I'm waiting because so far I haven't been able to beat the boss.

At second stage when masked dude appears with gargoyle (or whatever it is), do not attack the masked dude until the gargoyle is down.
You will get poisoned at one stage, which you should use Antidote to get rid of.
After that, just stay alive long enough and you should win the fight.