Karen is the Dark type elite 4 member in the games Gold, Silver, Crystal, Heart Gold & Soul Silver. Where Karen's team in each of those games consists of an Umbreon, Vileplume, Murkrow, Gengar, Houndoom, and honestly her team you can't really just bring one type and easily win, for the Umbreon & Houndoom, your best bet would be to use a Fighting type, Vileplume & Murkrow you could use an Ice type, then Gengar you'd want a Dark type of your own to defeat that, or something with a Dark type move. So yea, to defeat Karen, you basically need a mixture of types, you can't just rely on one type to win, which makes me love Karen's team. As well, I just love Karen's character design, and it is close to being my favorite character design out of all the Johto region characters. Overall, I love Karen greatly, but I honestly considered taking her out before I started my top 10, however, I kept finding more pros to Karen and more cons to the others I've already talked about, and I am honestly glad I chose to put Karen this high on my list, I just didn't think she was quite as memorable as the other 5 left, then the fact I have almost took her out of my ranking in past is why I opted to take Karen out right before my top 5.
Members Left:
Lorelei
Grimsley
Caitlin
Olivia
Acerola