Trivia:

An Ena uses she/her pronouns, as Joel Guerra refers to her as such.

An Ena's specie name could be a reference to the Japanese words "笑顔" (egao, smile) and "涙" (namida, tears), likely reflecting that she has a happy and sad side.

An Ena's masculine voice used to be voiced by Marc Rafanan in the first episode, but it is now voiced by Gabe Velez.

An Ena has a strong love for turrón, as revealed in Temptation Stairway.

One line from The Shepherd in Temptation Stairway implies that there is more than one Ena, presumably as a form of species. This is evident after Ena's encounter with The Shepherd, as she comes across a room of three other Enas floating in the void, sometimes glitching into Mannequins for a split second.

This is later proven through the Ena seen in Dream BBQ.

An Ena smells like chocolate milk.

An Ena's appearance at the end of Temptation Stairway is often thought to be her "full-happiness" form, but this has not been confirmed.