Guide
How the kit works
Start a fight with A Small Price for Victory when you can. It attacks the enemy and increases Clara's chance of being attacked for two turns after battle starts.
Because We're Family reduces damage Clara takes from enemy attacks by 10%. An enemy that attacks her gets a Mark of Counter, and Svarog counters for Physical DMG equal to 160% of her ATK. Her passives give her a 35% fixed chance to dispel one debuff when attacked, 35% resistance to Crowd Control debuffs and 30% more Counter DMG.
Use Promise, Not Command to reduce damage dealt to Clara by an extra 25% and greatly increase her chance of being attacked for two turns. It also gives Svarog two enhanced Counters when an ally is attacked. Their damage multiplier against the attacker increases by 160%, and adjacent enemies take 50% of the damage dealt to the primary target.
Use Svarog Watches Over You after enemies have been marked. It deals Physical DMG equal to 120% of Clara's ATK to all enemies, with another 120% against marked targets, then removes all marks. I Want to Help deals 100% of her ATK as Physical DMG to one enemy when you do not need the Skill.
Build and why
For relics, start with four pieces of Wavestrider Captain. It gives 16% CRIT DMG; abilities from other allies can give Clara up to two Help stacks. With two stacks, using her Ultimate consumes them for 48% ATK for one turn. Champion of Streetwise Boxing is another option: its Physical DMG bonus and up to 25% ATK suit Clara, who attacks and gets hit often.
For planar ornaments, use Duran, Dynasty of Running Wolves. Each Merit stack gives 5% Follow-Up ATK DMG, up to five stacks, with 25% CRIT DMG at the maximum. Allies' Follow-Up attacks build those stacks. Inert Salsotto is an alternative: it gives 8% CRIT Rate and, at 50% CRIT Rate, 15% more Ultimate and Follow-Up ATK DMG.
Use CRIT Rate or CRIT DMG on the body, ATK Percentage on the feet, Physical DMG Boost on the sphere, and Energy Regeneration Rate or ATK Percentage on the rope. For substats, prioritize CRIT Rate, CRIT DMG, ATK Percentage and then SPD. ATK supports Clara's damage scaling, while Energy Regeneration Rate helps her use her Ultimate.
Dance at Sunset is the first Light Cone choice: it greatly increases the wearer's chance of being attacked, gives 36% CRIT DMG and grants Follow-Up ATK DMG after the Ultimate. Thus Burns the Dawn gives 12 base SPD and ignores 18% DEF; its 60% DMG increase after the Ultimate ends at the start of the wearer's turn. The Unreachable Side gives CRIT Rate and Max HP, plus a DMG increase after being attacked that ends when the wearer attacks.
Leveling priority
Level Because We're Family first because it determines Svarog's regular Counter damage. Follow it with Svarog Watches Over You for damage against the whole enemy group and marked targets. Raise Promise, Not Command next, then I Want to Help.
For maximum ascension, you need 308,000 Credit, 65 Broken Teeth of Iron Wolf and 15 each of Ancient Part, Ancient Spindle and Ancient Engine. For all skills, you need 3,000,000 Credit, 8 Tracks of Destiny, 18 Shattered Blade, 69 Lifeless Blade, 139 Worldbreaker Blade, 12 Guardian's Lament, 41 Ancient Part, 56 Ancient Spindle and 58 Ancient Engine.
Eidolons worth it
Long Company is worth considering for the largest change to counters. When another ally is attacked, Svarog has a 50% fixed chance to counter and mark the attacker. The Ultimate also gains one more enhanced Counter.
A Tall Figure is a useful earlier upgrade: the Skill no longer removes Marks of Counter, so marked enemies can take its extra damage again. A Tight Embrace is another damage option, giving Clara 30% ATK for two turns after her Ultimate.
Family's Warmth is a defensive option: after Clara is hit, she takes 30% less damage until the start of her next turn. E3 and E5 raise skill levels rather than adding a new mechanic. If you are stopping at E2, you can leave those later upgrades for another time.
Teams
Pair Clara with a sustain character and a buffer. Huohuo is a Wind Abundance sustain option, while Tingyun is a Lightning Harmony buffer. They give the team different elements alongside Clara's Physical damage.
Clara gives the team damage when enemies attack, while her Ultimate lets Svarog answer attacks on allies too. Keep her need to be targeted in mind when choosing the rest of the team: fewer attacks aimed at Clara mean fewer regular marks and counters.
Common mistakes
Do not expect the Skill's extra hit against unmarked enemies. Before E1, it removes every Mark of Counter, so check which targets have been marked before using it.
Do not build only for damage and leave Clara without sustain. Her damage reduction helps, but she wants enemies to attack her. Also remember that her Ultimate has two enhanced Counters before E6, so do not count on those counters lasting indefinitely.
Check set conditions instead of assuming every bonus is active. Inert Salsotto needs 50% CRIT Rate for its damage bonus, and Wavestrider Captain needs two Help stacks when you use the Ultimate for its ATK bonus.