Which bane for Spring Kagero?

-Def because -HP hurts her ability to fight against mages.

-Def would be better for efectiveness since she's much better against mages. However, -def is a superbane which lowers her Arena score(BST bin). If you're concerned about it, use the -HP one. She's going to avoid doubles anyway, so even though it hurts her general bulk, it'll still be fine.

Both are good, which one comes to your preference. Do you focus on effectiveness and not too much about Arena score? -Def. Do you care more about Arena score cause you think she'll be fine? -HP.

If you're concerned about Arena scoring, use the -HP one. However, if you are planning to merge, then she will go back to her original scoring bin and you're better off with the -DEF so she can take on mages better.

Arena -hp bst150
Overall viability -def bst149

Not just one bunny titty, but a pair of bunny titties. Nice. Lmao

Now with that lewd reference out of the way, it depends on what you value higher, scoring or viability. HP bane hurts her magical bulk and defensive bulk, but a defense superbane drops her scoring potential, both now and in the long run if you decide to try to pull 9 more.