Mephisto was giggling to himself in his throne room, he just couldn't stop while he was thinking about all the special toys he has even though not all were finished yet. A sinister grin kept being plastered across his face when he was reminiscing about the creation of all of his toys.
At first he took over the throne and declared all non-human races as outcast to stabilise his claim on the throne. Luckily all the nobles that were his subjects welcomed this decision of his as the loved to use their power against people that were weaker than them. But Mephisto did not only want to get the nobility on his side, he also wanted a situation where no one would notice some missing people as he needed them for his test.