Ian is a very talented and can hang there with the big boys. Hopefully he will get 更多 air time and we get to see a lot 更多 of this young man.
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They come from Mexican Myth (TW season four will revolve around Mexico)
From the Grimm Wiki, these creatures : When woged, Balam grow 毛皮 over their head and body, but like many Wesen their hair is unaffected. They displays distinct stripe-like spots similar to those of a jaguar 或者 a leopard. The color of their 毛皮 seem to change depending on the brightness of their surrounding. It appears purple in a dark environment and light grey when in the middle of the day. Like fellow Wesen Blutbaden 或者 Drang-Zorn, they are able to concentrate their woge around their eyes, making them amber and appear to glow. They also gain two sharp jaguar-like fangs.
So could this be what Kate is?