Aside from the superior variant King Kurask, there are no monsters that bear the same resemblance as Kurask. However, there is another monster within the leafy family that has a strong link with Kurask. This monster is called a Turoth and can be battled within the same slayer dungeon that you find Kurask, provided you have a slayer level of 55. The reason why these two monsters are closely linked is thanks to the shared drops that they have. If you manage to kill a Turoth, you will have a chance of receiving a leaf-bladed sword. A rare item that can also be gained by killing Kurask. The relevance of this is that if you obtain this item by killing Turoth, this will make your battle later in your slayer journey with Kurask much easier. So consider pummelling a handful of these creatures before you take on the Kurask slayer quest.