While submerged in water, acts first and is invisible, and heroes have DIS on Initiative checks. Has a Swimming speed. Invisibility is canceled after 4 successful Bites.
Resistant to psychic dmg. Can't be detected by psionic powers.
- •Bite.
Swim 8, then (Reach 1) 1d10+15, on hit: Grappled, hero loses 1HD and the Fiend gains 11 temp HP; double that in case of crit. Can only attack Grappled target while Grappling this way.
- •Poison Tentacles.
(Reach 3) 1d10+5 to up to 2 creatures, STR DC 15 or dazed for 1 minute; if failed by 10+, incapacitated instead; end with counterpoison.
- •Synaptic Static (1 use).
(Reach 12) Concentration, up to 1min, any number of creatures in Range make an INT DC 15. If failed, all concentrations end, they can't use psionics and get DIS2 on any INT- or WIL-based roll (casting a spell, influencing somebody etc.); if passed, they can spend an extra Action to ignore those limitations.
At 130 HP, the Fiend automatically constricts the nearest hero (DEX DC 15 or Restrained). From now on, a crit with its Bite can only deal half dmg but another creature at Reach 4 is now Restrained: the Fiend will attempt to drown heroes while they are Restrained.
The Cistern Fiend is dying! 110 extra damage and it will bleed out. Until then, it doubles the Poison Tentacles targets and its Bite crits on a 8-10.