Titania Tank

Hi, I drew a -Atk, +Res Titania and was thinking of turning her into a defensive wall for a cav team rather than improving her attack.

Special: Iceberg
A: Fortress Defense
B: Guard / Undecided
C: Hone Cav

Should I swap her emerald axe to killer? I'm thinking of keeping guard since I'm kinda lazy to farm SP. But QR would be an alternative choice if I can spare.

For reference, I have Cecilia and Ursula as blade mages with Leo (no inherits) as my red dude. So Tit will be my only physical fighter.