How to win lane as Sion against Cassiopeia · 53.72% win rate (1,262 Emerald+ games, lolalytics, sampled July 2026) · Matchup data reviewed on patch 26.15
She kites you out — survive, then charge Q on the Miasma cooldown and out-HP the lane.
Track: Cassiopeia's W — Miasma (24–16s cooldown). Grounds you — dashes and movement abilities are disabled inside it.
Read from Sion's seat: which stage windows this plan plays for against Cassiopeia.
This is Sion's own plan; across 1,262 pooled games the lane is leaning Sion.
| Stage | Favoured | Why |
|---|---|---|
| Level 1 | Even / skill | Neither champion has their full kit — Cassiopeia lacks Miasma at level 1, so brush-angled Q charges are briefly possible, but she can still poke through Twin Fang spam without committing to melee range. |
| Level 2 | Cassiopeia | Miasma lands at 2 and grounds you, so you cannot start Unstoppable Onslaught inside it; every step forward is punished by poison, and it is only up every 24s at rank 1. |
| Level 3 | Cassiopeia | Her full three-spell combo (Q poison cloud, W Miasma zone, E Twin Fang) is now active; she pokes you through the wave and the grounding effect means your W-shield is your only real trading tool. |
| Levels 4-5 | Cassiopeia | Levels 4-5 are a pure kite war — Cassiopeia has no need to step in range, and your Q charge is telegraphed enough that she simply repositions; farm under your tower and do not chase. |
| Level 6 | Cassiopeia | Petrifying Gaze only stuns enemies facing her — charging straight in is the one thing that guarantees it, so use Unstoppable Onslaught to roam, or approach with your back turned and eat the slow. |
| First item | Cassiopeia | Heartsteel spikes your HP total but Cassiopeia's Twin Fang damage scales with her AP items simultaneously; the first-item duel still favours her sustained DPS and she can kite Heartsteel's proc range indefinitely. |
| Two+ items | Cassiopeia | Full-AP Cassiopeia's Twin Fang melts your HP pool in seconds at 2+ items and her Miasma denies any melee retaliation; never solo-duel her — force teamfights where your zombie passive and HP bulk zone her team. |
You cannot charge Q openly against Cassiopeia at level 1 — she has no Miasma yet, but her Twin Fang (E) poke punishes slow channels hard. Use the brush at the side of the lane or the wave itself as cover; if she steps up to last-hit a pushed wave she briefly leaves poke range and that is your only free charge window. W-shield absorbs one or two Twin Fang hits without meaningful HP loss, so do not panic-detonate it — hold it until you are ready to walk forward and she cannot poison through it fast enough to break even. Doran's Shield and a Magic Resist shard are mandatory; take Mercs if you expect Miasma to dominate the mid game.
Pooled Emerald+ win rates from Sion's side, sampled July 2026.
The full Sion vs Cassiopeia report continues with the mid-game plan, the late-game and teamfight plan, every power spike to play around, and the win conditions for both sides — plus cooldown tracking and the live enemy-jungle tracker inside the app.
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Sion, slightly — a 53.72% win rate edge over 1,262 games; execution can flip it.
Mostly — Sion has a small statistical edge (53.72% win rate), but execution decides this lane far more than the pick does.
Not a hard counter — Sion has a slight edge (53.72% win rate), and play quality decides the rest.
Sion takes Grasp of the Undying on the Resolve tree with Demolish, Second Wind and Overgrowth, and Precision secondary (Triumph and Legend: Haste) vs Cassiopeia.
Start Doran's Shield + Health Potion and back for Core component + boots (≈1300g). Build Heartsteel (W + passive love HP) first, then Warmog's Armor / Thornmail, with Mercury's Treads.
Playing the other side? Cassiopeia vs Sion guide →
All Sion top lane matchups →
More Sion top lane matchups: vs Ambessa · vs Aurora · vs Camille · vs Cho'Gath · vs Darius · vs Dr. Mundo