+Hp/-Spd Summer Leo help

I think you should keep him in case you don’t want to pull him again whenever he shows up on a legendary banner. First of all, Summer Leo has higher resistance and HP than both Sanaki and Lilina, so he’s better at tanking mages(even better with your +HP). And that HP superboon means he has 41 HP. You could try to capitalize on that boon and run him as a medic with Renewal and Ardent Sacrifice/Reciprocal Aid while also using Ploy skills either for both C skill and Sacred seal or just C skill, or even use Infantry Pulse with a lowish HP team(or use a +HP seal, that way you can activate Infantry Pulse even on neutral Brave Ike). I think his tome should be replaced for a Raudrowl, but for budget reasons his Tomato Tome will still do the job. Just give him the +res refine, Fury and maybe Distant Defense seal to tank magical hits even better, Defense Ploy(since you already have Attack Ploy) or the +HP seal if you want to run Panic Ploy or Infantry Pulse. B skill should probably be either Swordbreaker, Red Tomebreaker or Quick Riposte. Iceberg would be the best special imo.

Hope this helped!