This totally fits in with my headcanon that both these anime are set in the same universe, and that the Kamui are an early form of the Ganmen.
Through developing the Life Fibers, they will eventually discover Spiral Energy. The reason why Kiryuuin and Ryuko are the only ones (so far?) who can handle the Kamui is because they can utilize their spiral powers.
Ryuko is Simon's great great great great great great grandmother. Hair, color scheme, and even clothing are quite similar. Dark blue hair, blue and red clothing, midriff/chest exposed. The yellow on Senketsu's eyes is paralleled by the yellow on Simon's goggles.
Absolutely fucking ridiculous.