How to counter Sylas

He can copy all of those ults. Stop spreading lies.

For Jayce and Nidalee, he transforms into them with their full transformed kit until he recasts his ult.

For Karma and Heimerdinger, he gets a free augmented cast of one of their affected abilities.

For Kalista, he actually gets a free Black Spear in his inventory at the start of the game and can choose an Oathsworn ally for himself.

This sort of thing doesn't counter him at all. It just makes people think they can troll the people playing the new champ by playing somebody with a weird ult. No ult is safe.

He can use Nidalee, Jayce and Karma ult, those 3 are confirmed, not sure about the other 2 though.

No tanks. GG

He can copy Kalista R and he can buy Kalista spear

he has no counter at all, he is an all in bruiser mage, his build will be cheap and strong, he has waveclear, gap closer, heal, shield, 2 slows and a stun, who steals your ult, the only way he can lose is if his spells cost alot of mana and have super long cds, which currently they dont, so he is uber broken, welcome sylas to the league of perma ban allong with akali