Do keen senses such as scent or extra senses such as blindsight allow detection of invisible creatures or creatures in a darkness spell? So far we have ruled keen senses let one detect the space a hidden or invisible creature is in but still attack with disadvantage. But permanently blind cave dwelling creatures etc. who use only non sight senses attack normally. So often on a case by case basis.
[RPG] Can creatures with keen senses such as scent or extra senses such as blindsight ‘see’ invisible creatures
combatdnd-5e
Best Answer
Blindsight, definitely yes.
According to PHB p.291:
Blindsight counts as a special sense. And, pragmatically, a blind creature wouldn't care whether its target was invisible or in magical darkness, because they wouldn't be able to physically see them anyway.
Your keen sense ruling seems practical, and RAW.
Keen sense (based on a sense other than sight, of course) would give a creature advantage on perception rolls to determine the whereabouts of the target, making it more likely that the creature can pinpoint the location. But the target is still invisible, forcing an attack at disadvantage. (p.291 in the PHB again)