Yep, she's very wise, and also very tricky. Even if she's Reisen "pet". And she's hinted to be WAY older than the lunar rabbit. Tewi is over 1300 years old. Reisen is around 40 years old.
Tewi isn't Reisen's pet, but Reisen is technically her superior. They're both Kaguya's pets. Even so, they can't really tell Tewi what do, because she does whatever she wants.
They can't tell Tewi won't to do because Tewi only follows them of her own volition. It was explained by Eirin in Cage in Lunatic Runagate. Tewi is actually the ruler of all the earth rabbits! They only obey Kaguya because Tewi tells them to and Tewi is the one who let them live in the Bamboo Forest of the Lost in the first place (its actually her territory)! As Eirin put it, "We are not 'tolerating' Tewi, she is 'tolerating' us!"
