Despite being a greater demon as far as Slayer is concerned, and residing in the Catacombs of Kourend, Konar does not consider Skotizo to count towards a Kourend greater demon task. :
Old School Runescape HD Runelite Mod - Catacombs of Korend - Album on Imgur
July OSRS Poll Results
So I was trying out Skotizo with a black demon task... : r/2007scape
March 8th, 2019] Catacombs of Kourend, Skotizo, Abyssal Sire, and more! - Updates - Runex - The Best Economy RSPS!
Slayer Helm OSRS - Fast Points, Recolors & Imbued Version - GameDB
Old School RuneScape: The 10 Easiest Pets To Obtain