Who Counters Sylvan Sage Vivian in Epic Seven?

Frieren, Lady of the Scales, Shepherd of the Dark Diene and other hard counters counter Sylvan Sage Vivian. Her team sustain is the heal bolted onto her ultimate; an enemy that applies unhealable shuts that recovery off, leaving her as a single-target attacker with no party healing to fall back on.

Heal-blocking effects: Her team sustain is the heal bolted onto her ultimate; an enemy that applies unhealable shuts that recovery off, leaving her as a single-target attacker with no party healing to fall back on. Focus drain and repeated chip damage: Her debuff immunity and damage reduction both run on Focus, and the reduction spends a Focus every time she eats a heavy hit; sustained pressure burns the gauge below 3, after which control effects land freely on her. Avoiding her trigger threshold: Her damage reduction only fires when a hit is expected to be 30% or more of her max Health, so steady smaller hits and chip damage bypass it entirely and grind her down without ever activating the defense. The five-turn ultimate gap: Both her area damage and her only team heal live on a five-turn cooldown, so a team that bursts hard in the windows between her ultimates can race her before that single recovery comes back up.

In current Champion+ RTA, Perfumer Byblis has one of the strongest records against Sylvan Sage Vivian (60% win rate over 2,229 games).

Debuff-reliant control teams: While she holds 3 or more Focus she is immune to debuffs, so stuns, provokes, strips and DoTs slide off her unless her Focus has been drained, letting her keep attacking and healing through a control comp. Burst and assassin units: Any hit expected to deal 30% or more of her max Health triggers her to spend Focus for damage reduction, blunting nukers and single-shot assassins that count on one big hit to delete a squishy Mage. Slow, value-grinding teams: She pushes her own Combat Readiness every basic attack and takes an immediate extra attack at full Focus, so she snowballs turns and her stacking Attack buff against grindy defensive lineups that want a long fight. Whole-enemy-board comps: Her ultimate strikes every enemy at once while topping off her whole team's Health, so she trades evenly into wide teams by damaging all of them and undoing their chip damage in the same turn.