It's the multiplicative effect of both that makes him bullshit-tier when facing the Spiders.Iirc he has different powers depending on his condition. He's a conjurer but when he reaches a heightened emotional state his eyes turn scarlet and he becomes a specialist.
He made a vow that he would die if he used his chain to imprison anyone who was not a member of the Ryodan. That gave him an unbreakable chain and may have boosted his powers in the process. I can't exactly remember the explanation for his powers. It's either his Emperor Time activates in times of heightened emotion or his vow makes him even stronger.
The problem is that when he isn't facing them, he only gets the E. Time powers, and those have some pretty severe handicaps associated with them. They're also not great combat powers.