[ElConvoy]

That Sir are some very good questions.

The way Yggdrasil are presented they come of as a more juicy version of Smart Brain so I guess both have kind of equally styled ambitions of evolving the human race. The difference being one is a corporation run by the monters itself while the other harvests the power of the monsters. In Episode 2 we see them harvesting the Helheim Fruits while wearing some sort of Sengoku Driver to turn them into the lock seeds. I would assume Yggdrasils Goal is to use the Lock Seeds to make more and more Kamen Riders to evolve Humanity into a race of more powerful beings. This is also Indicated by Zangetsus line at the end of episode 2 were he comments on the appearence of Gaim as being a good thing for the corporation.

The Fact that People turn into Invess when they eat the fruits could easily be a side effect that is completely independent from Yggdrasils goals.