[quote=GuyYouWishYouDidntKnow]
You still haven't justified why he wasn't killed before he even got a chance to do that. Fragarach was used as a response to his trump card of the resonance, not Soul Purge, as was said. Fragarach responds to the trump card, regardless of if it's an attack.
[/quote]

Define trump card. Arguably, Soular Resonance is Stein's most powerful technique, but his most powerful attack is Soul Purge, the attack he used later. In ways, his trump card is soular Bond, which is also one of his most powerful abilities. What causes something to count as a 'trump card'?