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.
Complete Monster: The Undertaker was probably at his most evil in this era (even more than his Big Evil persona), as he admitted to killing his parents and burning his brother, attempted to kill Austin, and abducted many people to perform satanic rituals on them.
His "Higher Power" was hyped up to be even more evil and demonic than The Undertaker. It was revealed to be Vince McMahon himself. Setting up his own daughter's kidnapping just to screw Austin was the moment Vince became a Complete Monster and, rare face angles aside, he never turned back.
Evil Is Cool: The Undertaker personified this trope during his Ministry era.
Funny Moment: During a backstage segment, the Undertaker accidentally referred to his master as the "Hower Power". Made more hilarious by the fact that it's the Undertaker in his darkest persona and that he just continued the promo as if nothing happened.
This might be because, as one could see in his early years with Paul Bearer, Undertaker simply does not Corpse. No pun intended.
The Undertaker's issue was being demoted to the role of Vince McMahon's Dragon, however it would have happened regardless of who the Higher Power wound up being, as even before The Reveal the story become centered around the Higher Power rather than Undertaker. Not to mention that there are also many fans who felt that Vince was the best choice for the Higher Power and feel that any of the other potential candidates wouldn't have worked out too well and would have been examples of this trope.
It was more the fact that Vince being the Higher Power negated the entire Stephanie kidnapping angle, as it was revealed that Vince was just "acting" worried about Stephanie and faking his Villainous Breakdown the entire time (which of course he was in Real Life, but it was harmful to kayfabe).
The worst part may not have been who the man was so much as what the plan was. All this was explained as being for the sole purpose of screwing "Stone Cold" Steve Austin out of the WWF title—which Austin didn't even have at the time the story started! And it's just as likely in retrospect that this would've been the stated purpose for whoever was in the role as the most logical explanation—that the "Higher Power" had become deluded into thinking themselves a God of Evil, ala Vince McMahon himself seven years later!
In short, most people feel that the Ministry would have been much better if there was no Higher Power..
Memetic Mutation: "IT'S ME AUSTIN!!!! IT'S ME AUSTIN!!! IT WAS ME ALL ALONG AUSTIN!!!"
Moral Event Horizon: If the Undertaker didn't cross it when he admitted that he killed his own parents and burned his brother, or even when he tried to embalm Austin alive, he certainly did when he abducted people such as Ryan Shamrock and Stephanie. Vince McMahon being the mastermind of the whole thing was HIS crossing of the Moral Event Horizon.