Birkin wasn't much of an antagonist before his mutation, but yeah his first form, where he shadows his human appearance but has the arms and talons and all. They were the dynamic duo for sure, I loved them in RE0, and I wish we could have seen more of them...
I have a top 5 thing I usually do:
4 & 5. Alternate among the these three, Chris, Jill & Claire.
My favorite game is probably REameke. My favorite character...well I would have said Wesker with no doubt, as he was my fav, but his recent appearances have really lowered him for me. I might still go with him, but I think that him and Birkin together are my favorite. My favorite enemy is Birkin in his 1st form.