https://minecraft.fandom.com/wiki/Minecraft_Dungeons:Heart_of_Ender Story

The Heart of Ender is the manifestation of the voice that the Orb of Dominance speaks to the Arch-Illager with, as seen in the book The Rise of the Arch-Illager. Through the various actions Archie committed during his reign as the Arch-Illager, it can be assumed that the Heart of Ender is vile, sadistic, cruel, and merciless, akin to an embodiment of pure evil itself. It shows no remorse or guilt for its actions, as shown by Archie’s personality when he was a proxy to the orb. Its main goal is the complete submission and loyalty of all living beings, no matter what is necessary to accomplish its desires. The only other emotion equal to its cruelty is its hatred towards its enemies, a hatred so strong that it continues to burn postmortem. This said hatred can sometimes eclipse its intelligence, as its shattered conscience was willing to spread its corruption throughout the land even though those actions put its well-being at risk. Its arrogance eventually came to head when its desires for revenge revealed to the world that it survived and had been reborn and currently residing in The End. Another example is that when reborn, it was willing to destroy the very world it wished to control.

Appearance

Appearance The Heart of Ender is a large, half translucent hostile mob that resembles an Enderman. Its head is similar to an Enderman’s, but it is slightly elongated and has a more toothy mouth. It has six tendril-like appendages attached to its torso, which also give the Heart of Ender the ability to crawl.

thanks sans is justified and punny for the light effect given to this design

(Original template by this guy https://www.youtube.com/watch?v=hoCaCmwhLGY&t=239s)