-Spd +Res Leif build help?

I want to make use of Leif, but his IVs are just.... yeah. :/
Any way he could be made use of?

EDIT: Thought I'd make an edit to show what he's like as of now to get a better idea and see if the build is okay.

IVs: +RES | -SPD
Weapons: Light Brand
Support: Reposition
Specials: Moonbow | Ignis
Passive A: Death Blow 3 (waiting on getting Swift Sparrow 2, may use Atk/Spd Bond 3 but not sure.)
Passive B: Quick Riposte 3 | S Drink (only for Tempest Trials purposes.)
Passive C: Drive Atk 2
Sacred Seal: Speed +3 (may change that)

Thoughts? Any changes that could be made? Any helpful feedback/changes would be heavily appreciated. :)