Daniel Sharman plays abused teen beta werewolf, Isaac Lahey, abused da his own father and he was the first member to unisciti Derek's pack and was the only one who stayed in the pack when Erica and Boyd were kidnapped da the Alpha pack and was in a volta, vault for 3 months and Erica was killed da the Alpha Pack and Boyd was accidentally killed da pack leader, Derek, and was a big help to Derek, Scott, and Chris da helping to defeat Gerard and the Kanima (Jackson). And he also helped Scott, Derek, Chris, and Allison to stop Boyd and Cora from attacking innocent people da trapping them in the school's boiler room, So three cheers for Isaac!
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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 pelliccia 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 o a leopard. The color of their pelliccia 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 o 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?