Like Hellhounds,Cave Krakens have a high Slayer task weight,meaning they're a frequent assignment that you'll want to RuneScape gold avoid. These monsters also can't be killed using melee or ranged combat,limiting you to using a Trident of the Swamp or other single-target magic weapons. Their drop table is also lacking,with few valuable items to offset the slower kills. For these reasons,Cave Krakens are a prime candidate for your Block List,as they take considerable time to kill while offering minimal rewards.

Black Dragons
Black Dragons are another task that may seem like a good challenge,but ultimately is slow and inefficient. Not only do they have high hitpoints,but you'll need either an Anti-Dragonfire shield or an Antifire Potion to protect yourself from their devastating breath attack. While you can earn Dragon Bones for Prayer XP,they also have high defenses and require expensive equipment like the Dragon Hunter Lance for optimal kills. Plus,Duradel typically assigns only 10-20 of these dragons,which isn't ideal since you're aiming to kill large groups of monsters to maximize XP per task.

Greater Demons and Black Demons
Both Greater Demons and Black Demons should be blocked for similar reasons—high Slayer task weight,poor loot table,and inefficient XP. Duradel assigns large quantities of these monsters (typically 130-200),meaning you'll be stuck killing them for long stretches of time without gaining significant XP. Moreover,these tasks can be frustrating since you often have to compete with other players for kills,leading to slower kills and wasted time. While these demons can be useful for Ironman accounts due to their shared Demon classification (allowing for the use of the Slayer Helm),for most players,the inefficiency of these tasks makes them a poor choice for RS gold for sale leveling Slayer.