+HP/-ATK Swordhardt

I dunno, Death Blow 3 + Hone Cavalry, I guess?

Even with an attack bane, he can reach like 37 attack with Hone Cavalry.

IF you have plenty of spare fodders, you could probably try something like making him more of a defensive tank since his defensive stats aren't too bad when combined with a horse team. I would probably give something like CD/DD on A and seal slot. Vantage B slot, C slot depending on horse team, Repo, Moonbow/Bonfire.

Otherwise, I would just use his base skills.