[[Hazel]] will charm the party such that they can feel an internal pull towards the lair, a magical internal compass.
The black dragon's name is Venik, though it may not say it out loud if unquestioned.
It will ambush them (minus Lili) and immediately spray acid.
Next round it will submerge.
Then it will come out to attack the most isolated member.
Once bloodied it will become enrage and attack anyone closest. Advantage on attacks and disadvantage on being attacked.