Make the Exorcist Fall in Love - Ch. 94 - Shadow

[MangaDex]

 

[Helscythe]

So if I'm assuming correctly Mr. Priest became unworthy of the power of the angels, but instead gained favor with the Sins and as such can manifest their powers or even summon them.

The condition to summon them would probably be a surplus of emotion with the associated Sin, which is why Mammon showed up because of the wish of Mr. Priest.

 

[CrimsonSix]

Lucifer really is showing why he stands at the apex of the sins.

 

[animan095]

Damn Lucifer is a badass, gave me chills when he said "Aside God and the Angels, I am the strongest being in this world"