Plays well with
Riven
The Exile
With Riven's mobility and potential damage on his side, they can hunt any champion down and deal massive damage in teamfights. Their skills synergize very well. Riven can stun her enemy, while Sigil jumps in lane, dealing damage and slashing around just like Riven. Together they are an infamous duo.
Yasuo
The Unforgiven
Yasuo can lock his enemies down with his ultimate and deal massive damage. His chase potential is great too. Because of this he works very well with Sigil; when Yasuo has locked down his enemy, Sigil can go loose with his bursting abilities.
Sivir
The Battle Mistress
Her shield, ultimate and Q are deadly skills especially for Sigil. She can just counter his Q>E combo with her shield, disengaging with her ultimate all while dealing damage to Sigil with her Q and basic attacks. When the enemy has a Sivir, Sigil's chasing ability is pretty much fully countered by her ultimate.
Struggles against
Janna
The Storm's Fury
With her strong disengage potential, she can make sure Sigil can never reach her allies. She has just the right ingredients for a Sigil counter.
Diana
Scorn Of The Moon
With Diana's burst potential, Q, W and ultimate combo, she can burst the squishy Sigil down and keep reaching him. Very hard matchup for Sigil.
Lee Sin
The blind Monk
Lee Sin outsustains Sigil very hard and he can be a pain in the ass for him the whole game. Our blind monk can kick him away, deactivating Sigil's chase. On the other hand, he can chase Sigil easily when he tries to run.