Kundun Shield Skill to other Bosses

Basically, Kundun has the greatest boss/monster skill in-game. The shield that delays its death by a lot, making it harder to kill that bosses with 3x more HP and defense. 

A kundun with 100 million HP is harder to kill than a God of Darkness with 1000 million HP. But it would be nice to implement this skill to every boss in-game so they all become difficult to kill (sometimes bosses are easy to kill due to high damage, this prevent bosses from quick dying and not need to increase hp and defense to extrem high levels).

I searched for this skill in monster skills but couldn't find it.