[quote=@harinezumikouken]
[@VitaVitaAR] - Since both Zetsuko and PKMNB0Y responded, am I good to make another Marianne post?

[@Raineh Daze] - Somewhat unrelated, but Tyranthe can only perish if she's beheaded, right?
[/quote]

Or split her head. Both of which aren't exactly commonplace or easily achieved. And to make it harder, her throat's even more heavily armoured than the rest of her. 

But yeah, that's how you kill sentient undead.