|With the addition of the Savage Blow seal and the plus versions of staff weapons to the game, this opens up some interesting possibilities for staff users that just weren't possible before. This build, which I like to call Dazzling Shrapnel, capitalizes on the splash damage ability of both Savage Blow (the skill as well as the seal) and the Pain+ staff, which both deal flat damage (unaffected by enemy def or res) to enemies within 2 spaces of the target after combat. Pain+ deals 10 damage while Savage Blow 3 deals 7. These numbers aren't very impressive...until they are all stacked!
With Pain+ for her staff, Savage Blow 3 for her C slot, and the Savage Blow 3 seal, Clarine will deal a whopping 24 flat damage to all enemies within 2 spaces of the target, which is massive for any unit, and especially impressive for a staff unit. Now, with the addition of the dazzling staff refinement on her staff and Wrathful Staff 3 for the B slot (these can be switched depending on what fodder you have available), Clarine will not only be able to do this damage safely, but will also do a fair bit of damage just with the base attack itself.
An Atk+ IV with Attack 3 for the A slot is preferred to maximize her potential damage. The reason for this is because neither Pain+ or Savage Blow can kill an enemy with the damage dealt after combat, which means quite often you will have enemies with 1 hp remaining after attacking a couple times. Having the highest possible damage gives you the best chance at being able to finish these enemies off. With Atk+ and Attack 3, Clarine will have an attack of 42, which is enough to deal at least 1 damage to every hero in the game as long as they don't have any buffs to res or skills that increase the res stat, and even then there are only a handful of characters capable of reaching that high of a res stat even with buffs. Having a high Atk stat will also help with many of the healing abilities as most of the plus variants increase healing based on the Atk stat. With all that said, if you don't have access to wrathful staff, I would still definitely suggest using the dazzling staff refinement and then going with a Spd+ IV and Speed 3, that way you still don't have to worry about being countered and with the extra speed you will have a better chance of doubling enemies, which will do a little more chip damage to enemies with lower res and will charge your special faster.
Which brings us to the special. This is flexible, although I would recommend Miracle. It does have a high cooldown, but, with Clarine's high speed, and the inability to be countered, you can safely charge Miracle with a few attacks and then she'll be a pain to kill. Even if you only get 4 attacks off before she gets attacked, it will only take one attack from an enemy to fully charge it, and even with -HP and neutral Def, an enemy will need an Atk of at least 54 to one shot her, and if they can't and are able to double her, the second attack will proc Miracle. If you're not too concerned about her survivability, you can always use Imbue for extra healing, or one of the balms for some stat boosting capability.
Lastly, for her Assist, I would highly recommend you stick with her innate Martyr+, which synergizes quite well with Miracle as it does extra healing the more damage she's taken and after Miracle procs, Clarine will be primed to do maximum healing. Other healing abilities like Physic+ and Rehabilitate+ can work quite well too, so just use whatever works best with your playstyle.
This build is a very high investment, so make sure you're ready and willing to commit to Clarine before beginning. If you do though, you'll find you have a really interesting and useful character in your arsenal that can be useful in many situations. Add a dancer to your team and she becomes a force to be reckoned with. Put her on a cavalry team and she just gets more potent.