D&D 5E Marilith reactive thingy

[MarkB]

If the Marilith had a ready-on-every-other-creature's-turn Reaction to attack an enemy that moves out of her AoO zone, and an ally that can do this : You frighten one creature which must immediately use its Reaction to flee your presence ... then the ally can scare a PC to send it running, and the Marilith can whack the PC on his/her way out - on the ally's turn. If the Marilith has several such allies (and is standing next to the Exit), it could strike several PCs before its own turn came up again.

Hmmmm...

Alternatively, give it several Battle Master allies each using Commander's Strike.

 

[Rabulias]

If the Marilith has several such allies (and is standing next to the Exit), it could strike several PCs before its own turn came up again.

This is similar to the broader strategy for creatures with Legendary Actions to have lots of allies/minions, increasing opportunities for it to use its Legendary Actions...

 

[Flamestrike]

Alternatively, give it several Battle Master allies each using Commander's Strike.

Give her PAM and Sentinel feats, and three Glaives for the lulz.