Token 10000 year old loli.
Token animal girl.
Token big sister.
Token deus ex machinae.
I don't mean that in a sexist way.
Think about it: what purpose did she serve to the plot other than being waifu bait? What purpose did the big sister serve to the plot other than being waifu bait?
I've given it some thought and I think the purpose of Fredrika is to pin me down with her doomclaws and ravage me. Not using rope or anything, just using her powerful dragoon hands to keep me in place so that I know she has complete power over me. Just rape me to pieces. Savagely milk my pathetic penis until I can barely breathe. Loom over my face so that her hair falls over us both and forms a golden curtain around our faces so that I can see nothing but Freddy. Make me futilely struggle for air when she forces her slimy monster tongue down my throat.
Claw me, abuse me, bite me. Break me down into her toy until I fall unconscious and wake up later completely healed, being petted and hugged like a daki.