Afaik only Dream Spirit and Sky Spirit can go slightly above 300 def when perfectly rolled on 10-15%ed bases
I'll leave you a couple beauties I rolled for myself in case you wanna consider them. Sun Spirit base is 11%ed so currently perfect roll, and Blood Spirit base was 13%ed if i recall correctly, so it could still be rolled with 4%ed more than it currently has:
https://i.imgur.com/lBWUuiC.png