2 -RES/+HP LA!Roys

Use him on a team of Brave Lyn + dancer. That's what I would do. XD

If you plan on using the Roy, a 5* +1 merge is never a bad thing. His skills don't look awfully rare for SI, unless u wanted to do something with Gratia. So maybe merge, give him Distant def seal, and he'll be your tanky archer cavalier boy. :)