Plague Host

Two women in dark blue robes were sitting across from each other inside a small hut. The first one was looking at her friend expectantly, while the other was holding a few pages of paper that was handed to her.

"Hurry up and read it!"

"Yes, yes..."

The second woman sighed, not really looking forward to finding out yet another horror that her friend had created. As former humans turned immortal witches who had been living for centuries, mundane activities and boring days were their worst enemies. But while she was content watching over mortals in their daily struggles, occasionally helping them if she felt like it, her friend was more into outlandish experiments. But it could not be helped, she understood that her friend was just built that way. After all, one of her outlandish experiments was the very thing that enabled them to attain immortality by suspending their age indefinitely.

"Let's see... A parasite? Really?" she frowned, shooting her long time friend a questioning look.

"Not just any kind of parasite! Read further!"

Humoring her friend, she continued reading the paper. Said friend drew inspiration from parasites that infect other organism to control their behaviours. Worms which insects to drown themselves; maggots that makes snails to predators; fungi that ate an ant from the inside to become their breeding ground. But she wanted her parasite to be greater than those. She wanted to create one that can control the Great Races, which consists of humans, elves, beastkins, and several other dominant humanoid races in the known world.

"Are you crazy?!" was what she wanted to shout out loud, but her friend herself knew she's crazy, a 'mad witch' she once called herself. And so the saner witch continued reading in hopes of finding any measure to combat the parasite. Instead, she only found the extent of its power.

"Once the parasite attach itself to the first host, it will absorb and mimic the host's personality and taste as it grows into maturity. The parasite will then propagate inside the first host, subsequently called Primary Host, and its larvae or other types of offspring will be able to infect new hosts, subsequently called Secondary Host(s). Once it is / they are fully grown inside a Secondary Host, the offspring can change the behaviour of the Secondary Host to match the Primary Host's personality and/or taste. They will also feel inexplicable need to obey the Primary Host's wish and would be loyal towards them, though the extent of this second and third effect would depend on the Primary Host's and Secondary Host's prior relationship before the infection"

"Primary Host? More like Plague Host!" she screamed inwardly, "if there's an uncontrollable outbreak, this could potentially spell the end of the world!"

"How is it? Isn't it great?" the mad witch said the, oblivious to her friend's inner turmoil.

The witch looked up from the paper, glaring at her friend, "great? You've created a terrible thing!"

"I know! Aren't I awesome?"

She slapped her own face and groaned, "this isn't something to be proud of!"

"Ehh... But you gotta admit it's an amazing creature, right? And depending on the type of parasite, they might have other special characteristics or abilities! It took me a long time to decide on a type to develop, but finally I created one that suit my taste! Just look at the illustration I provided on the second page!"

The saner witch returned her attention back to the paper and flipped the page. What greeted her was a very detailed sketch of...