Sinding, Were-cursed

Whenever another Human dies, put one +1/+1 counter on Sinding, Were-cursed, if there are
more then three +1/+1 counters on Sinding,
Were-cursed you may sacrifice him, if you do, put legendary artifact named Ring of Hircine onto the battlefield.
{p/r},{p/r},{t}: Put one -1/-1 counter on Sinding, Were-cursed, if Sinding, Were-cursed is killed this way, put legendary artifact named Savior's Hide onto the battlefield