Ultimate Skill

Ultimate Skills (究極能力) are the successor to Unique Skills and the final evolutionary stage of Skills in general.

Characteristics
Ultimate skills, as the name implies, grants its wielder the ultimate power to control the very laws of nature. The only way to counter an ultimate skill is with another ultimate skill. That is the absolute, unbendable rule of the world.

If unique skills are born from one's individuality, ultimate skills are born when unique skills are brought past their limit. That is why no ultimate skill is identical.

As the story progresses, it is revealed that through certain methods, ultimate abilities can be imparted to those who have not naturally awakened them. The only requirement, like natural ultimate skills, is that the recipient must be a Spiritual Lifeform to qualify for it.

Angelic System
Angelic System (天使系) are a line of ultimate skills directly created by Veldanava, each bearing the name of angels. Among them, the most powerful are the Virtues (美徳系), seven skills born from isolating Veldanava's divine authority over creation. After the world stabilized, he kept Michael for himself, divvying a few to those he considered worthy, and released the rest into the wheel of reincarnation to choose their own masters. As they were too powerful, they were occasionally restricted to the unique skill level.

All the ultimate skills of the angelic system are linked to Michael with narrow corridors directly built into them during their conception, making their holders subject to the absolute control of Michael.

Demonic System
Demonic System (悪魔系) are ultimate skills born as counterparts to the angelic system. Among them the most powerful are the Deadly Sins (大罪系), seven skills corresponding to a person's fundamental desires. Though born as imitations of the angelic system, demonic skills boast the same potency as their angelic counterpart. Demonic skills, like their Angelic counterparts, also tend to choose their masters, occasionally sprouting within them as degraded unique skills.

Trivia

 * In the story, the characters pronounce Ultimate Skills using only the being they reference and not the entire names used in the wiki and translations. Meaning, it's "Ultimate Skill Beelzebuth" not "Ultimate Skill Lord of Gluttony Beelzebuth." This is due to the Japanese texts themselves. (See: Furigana and Ruby Characters)