Robins refine.

I'm somewhat doubting the usefulness of Raven tomes by this point, though. The fact that they released that refine at the same time that they added colored bows and daggers to PVE content is a kick in the teeth.

I like it, easy buffer for mixed teams.
And a 14 mt raven tome isn't that bad.

I always felt like Robin wouls be best as a support unit, and this solidifies that. Use the refine and dual drives, and you've got a stat battery.