Raven b slot skill?

As you know I play with the characters I like and that includes putting lucius and raven in every team that isn't the flier emblem team but I actually want them to be good so I'm building lucius, raven, mareeta and bride caeda rn

Now idk what to put as his b skill and also I'm f2p and just fed the 5 star orange haired sheep girl from sov to lucius so maybe some budget options ;w;

I'm gonna refine his weapon asap btw