Do you use it on ultimate enhanced rare cards too?

Slurp! It's quite meticulous of you to consider using rare cards for the growth of essential raid heroes, hmph! If there are superior alternative heroes, using rare-grade ones as ultimate enhancement materials is a wise choice. However, it's only reasonable to kindly keep heroes useful in specific dungeons, like Helenia, hmm!

Yeah, that's how it should be done.

Does ultimate enhancement apply to all heroes?