About the lore part, Tomoe is an Okami warrior, this is a matter of fact. Also Tomoe is her name(much like Shizu), not a clan. Okami is the species that she is part of, is just a matter of her ranking in the warrior society; most likely a purple garb since blue ones can't use lightning. The Floating Passage art should explain it clearly; she descended the unseen stair way (the straw man elevator most likely) from the palace to the world below, do you see any other warriors in the palace that are not Okami(besides the corrupted monk)? Also the skill's artwork clearly depicts a Okami Warrior Woman, just like those encountered in the Fountainhead Palace, I am really not sure what other proof you would need.