Ophelia C Skill help

It's a C slot so it doesn't matter as much. If you have odd atk wave then that'll probably be her best option but that's a rare skill so that's asking for too much. Threaten skills are an option but eh I would much prefer to use a hone/drive/tactic skill over threaten skills. You're also running a chill skilI so not much need for a threaten skill.

Savage Blow is a nice way to deal chip damage. Otherwise, her best C skill would be a wave skill, though they're pretty expensive options.

Support the team with a drive? That's pretty much never a bad idea, just that there are sometimes better ones.

Savage blow if you're using AoE special, but you're not, so atk, spd, or def smoke could also be considered. Atk smoke helps your tanks or glass cannons who haven't yet activated desperation; spd smoke helps both fast tanks and speedy attackers; def smoke can seriously mess them up if you have a fast brave weapon on your team.

Or if you have fodder to burn, close guard. I guess that goes in the drive category.