These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Tiberius is a sickening, perverted, undead Necromancer who finds being a rapist, pedophile Serial Killer the most fun he could possibly have. Tiberius is despised even by most of his compatriots in the evil organization Anticross for his activities, Tiberius attempts to kill, rape, or steal the soul of anyone he comes across, no matter their age or gender.
Vespasianus is a Mad Scientist of Anticross who goes past his compatriots in the lines he'll cross. Vespasianus kept a boy named Ryuuga hostage and experimented on him to turn him into the black angel Sandalphon, manipulating Ryuuga and his beloved sister Leica into fighting one another. Vespasianus made sure Ryuuga would have a new, deep hatred for Leica. Consumed by his experiments, Vespasianus cares nothing for morality and also assisted the Deep Ones in attempting to revive their destructive God Dagon to satisfy his curiosity.
Nya, AKA Nyarlathotep is the true Big Bad of the whole setting, having setup all the events, allowing Anticross to cause so much pain and suffering, as well as their experiments and the bloodshed that resulted. Her cruelty is such that she attempts to create an Eldritch Location where a hero who opposed her is forced to relive his life over and over, coming close to seeing his true love again, but resetting before he could get to her. Nya's ultimate goal is to release Azathoth and the other outer gods to consume everything, relishing in nothing more than humanity's suffering.