Staff of Serpent : Leviathan -
The Staff that originates from Leviathan, the Staff could transform into the Demonic Serpent or True Dragon Leviathan that wander the Earth since the Genesis of the Planet, the user could put Leviathan under their Command. The rank is "-" because he has "devoured" the Leviathan.
Immense Evolution Drive EX
Beast VII constantly remodeled his Saint Graph multiple times, as the result his stats fluctuating and were full of "+" modifier. He was originally a fur ball monster that crawl in Belly of the earth and continue evolving to a monster with True Dragon Corpus. As he evolve the Demon Gods Pillar who merged with him evolving as well as the result they become Draconic Demon God.
Source

( From right to left; Zepar, Baal, Phenex, and Barbatos )
Monstrous Strength A++ (True Dragon Corpus)
One’s ability as a monster. This Skill raises the user’s Strength. At this rank it is at about the highest possible level. Once he manifested his True Dragon Corpus, he will get this skill and no one will be able to stop him.
Memoir from the Apex
Magia Record A
The Record inherited from the Ten Rings of Solomon. Memories, abilities, experience, and body, he inherited these things from the former user of the Ten Rings i.e. King of Demon Gods, Goetia. Having inherited most of Goetia's memories he knows everything about Chaldea, thus he assumed Romani's body to wander around the world and since he have no True Name, he started to call himself "Chaldea Man"
Clairvoyance EX
Eyesight of good quality. Apprehension of long distance target and elevation of kinetic vision. When the rank is high enough, even x-ray vision or future prediction becomes possible. Nameless' Clairvoyance gives him unobstructed view of both the past and the future.
Rings of Solomon EX
The ten rings given by God. The mark of the king, the progenitor of magic. In the case of all ten rings present, any and all kinds of magic performed by mankind is invalidated and put under his subordination.
Evocation EX
A skill inherited from Goetia. Magic that evokes of spiritual bodies of the past, or perhaps the future.
With his Evocation ability that spoke of the summoned spiritual existences, the "Seventy Two Demon Gods", and established them as capable familiars.
Nega-Summon ⭐(Matured)
Another Authority inherited from King of Demon Gods Goetia. Cancels all Noble Phantasms of summoned Servants either by absorbing, nulifying or negating them all together. Unlike Goetia, there is no "exception", thus the skill retain its original rank.
The moments he reached matured state, he will gain this authority.
Nega-Terminus A
Original Skill of Beast of The End, the complete opposite of Tiamat's Nega-Genesis. Upon it's activation it will trigger and accelerate countless disaster upon the earth. Eruption, earthquake, giant wave, typhoon, even rain of meteors. As expected the beast by no means invincible, all these disaster could also potentially killed him, he particulary scared of Dukhan (Dust of Star that Covers the Earth) or to be precise the gigantic meteor that caused it, as expected not even him can survive a direct hit from a giant meteor that could produce Dukhan as the aftermath of it's impact.
Once this skill is activated he will return to the Inner Sea of The Planet and devour the soul of the planet. It is only after he succesfully devour the soul of the planet that he will become a fully matured beast.