Before level 5, Evelynn has weak jungle clears and low solo damage with a fragile body, so Sion tanks her Allure (W) charm combo with Soul Furnace (W)'s shield and high health, then counters with Decimating Smash (Q)'s knockup to dominate early skirmishes.

Before transforming, Kayn has weak sustain and low solo damage, so Sion tanks through and uses Decimating Smash (Q)'s knockup and Roar of the Slayer (E)'s slow to win early skirmishes and delay his form completion.

Zed struggles to burst through Sion's Soul Furnace (W) shield and high health, and his Living Shadow (W) combo gets interrupted by Decimating Smash (Q)'s knockup, so tank Sion wins extended fights.

Nidalee pokes the mobility-starved Sion from outside his range with Javelin Toss (Q), easily sidesteps his charged Decimating Smash (Q) and Unstoppable Onslaught (R) dash, and seizes jungle tempo with faster clears.

Dr. Mundo's Infected Bonesaw (Q) deals max-health-percent damage, and Maximum Dosage (R) plus his passive regen let him ignore and melt through Sion's tankiness, so Sion can't win a health war.

Warwick chips Sion's health with Eternal Hunger (P)'s bonus damage and sustained lifesteal, and Infinite Duress (R) suppresses him to cut off Decimating Smash (Q)'s charge, dominating extended fights.

Olaf's Reckless Swing (E) deals true damage and Ragnarok (R) grants CC immunity, letting him ignore Sion's Decimating Smash (Q) knockup and Roar of the Slayer (E) slow while winning extended fights with lifesteal.

Fiddlesticks uses Terrify (Q) to interrupt Sion's Decimating Smash (Q) charge, and Bountiful Harvest (W) deals max-health-percent damage while healing to ignore his tankiness and overwhelm extended fights.