Dendar the Night Serpent is a snake god trapped in a planar prison. Her goal is to escape her prison and eat the sun. She is worshiped primarily by yuan-ti. Wumba, the batiri goblin, is a devotee of hers as well.  When the waffle crew was traveling to Orolunga, they stepped on to holy ground of Dendar. A facsimile of Dendar appeared and attacked the group. Evelyn cast compelled duel and battled it one-on-one, but Dendar turned to mist before the battle could be resolved.  The oracle at Orolunga warned the group that Dendar wants to eat the sun.  While exploring the yuan-ti temple in Omu, the group came upon a large temple of Dendar. 
While in the temple, some of the waffle crew experienced strange nightmare journeys fueled by Dendar. Evelyn appeared in the tomb, Diath visited a strange version of Waterdeep where Fenthaza asked him to lead the yuan-ti, and Strix appeared in a maze with a person named "Ubtao".