(This is for the older readers, since I'm copy pasting this into chapter zero so that new readers get the idea from the beginning)
Okay, it seems some things appear to be unclear.
The Main Character (Samael)'s power and place in the cosmic hierarchy that is DC.
Out the gate, I'll say he's below Michael Demiurgos, Lucifer Morningstar and slightly below Gabriel Hornblower.
He's above the endless and the other non-demiurgic archangels.
So in DC, he's currently Top 5.
1: Yahweh/The Presence
2/3:Lucifer/Michael (interchangeable really)
4: Gabriel Hornblower
5: Samael Luthor (Our Main Character)
Now, the question Supernatural fans are probably asking: how the fuck did you upscale him this high? This is Bullshit!
At least, that's what I think some of you would say.
Well, verse equalisation!
By that, I mean this.
In Supernatural, Chuck/God is the literal living concept of Creation, Life, Light, etc.
The Darkness the living concept of Destruction, Erasure, Darkness.
Death the Horseman, the living concept of Death, literally just Death itself.
Doesn't this sound a bit familiar to what the endless are?
The endless being living concepts are that powerful, it is because they are what they are in DC that they are so powerful,
its the nature of things (since personally I agree with DC's interpretation of how strong beings of this nature should be an believe Supernatural didn't do them justice.)
How does that scale Lucifer from Supernatural so high and by consequence our MC who has his grace I.e. his archangel essence, making him, essentially, Lucifer - just not personality, but cosmic status?
Well, Lucifer in s15 one-shot Death after getting boosted by Chuck.
A boost I personally believe to be lesser than the boost he had when he absorbed Jack's grace at the end of season 13, which is the power Samael (our MC) has.
And don't say, Supernatural Death was replaced, the endless can also be replaced, Dream was replaced after all, it doesn't dimish their conceptual power and status that Supernatural should share by consequence of verse equalisation.
Since you can't have Death itself in DC be Outerversal and Death in Supernatural be Multiversal when they are literally the same thing in essence, one is a woman and the other is a guy, but their power shares the same root, being Death.
So to make it logical with DC and all, we'll say the Supernatural show in this Omniverse I am writing hadn't shown it simply - that level of power.
Now, what can Samael Luthor do?
Anything but create his own perfect vessel and kill Michael Demiurgos, Lucifer Morningstar and Gabriel Hornblower with ease. (Basically like DC Lucifer, who can do anything but create from nothing and kill his twin Michael and younger brother Gabriel instantly)
If he gains his perfect vessel though, he'll gain an equal boost that Michael in Supernatural got when possessing Dean to not possessing him, meaning, Samael will be able to contend with Michael Demiurgos and Lucifer Morningstar.
So, yeah, he can do anything besides that, he can even create from nothing, since his Grace is part of Chuck(who in this fanfic is an aspect of Yahweh, like Yahweh has all those other aspects in DC, and Supernatural Lucifer is basically a prototype of DC Lucifer),
And Chuck is literally Creation itself as is Grace said to be.
But, unlike Michael Demiurgos, he can't create something infinite from nothing, nor can he manipulate it to an infinite scale like DC Lucifer can.
So, once again, the rankings.
1: Yahweh/The Presence (Top of the Omniverse)
2:Lucifer Morningstar/Michael Demiurgos/ Samael Luthor (with Perfect Vessel)
3:Gabriel Hornblower
4:Samael Luthor (without perfect vessel)
5: The Endless
And then so on the rest of DC.
Well, hope this cleared things up and I hope to see you all later,
Bye!