Undead troll

The undead troll is a monster that, as being undead, is vulnerable to the effects of a Salve amulet or the Crumble undead spell. It can be alternatively killed for a troll slayer assigment. They are surrounded by Elite Black Knights, that are agressive, unless you are wearing Dagon'hai robes or Elite black armour. When you rearch the trolls spot, you no longer need to wear those. To acess them, you need to have some progress on the While Guthix Sleeps quest. Those seem to drop a good amount of blue charms.

Habitat(s)
The undead trolls live in Lucien's camp. To acess this camp, you need to go to Surok's room at the end of the Black Knights' Fortress dungeon, than activate the Strange teleorb. You'll need to have a death and a law rune in your inventory.

Other drops

 * Nothing
 * Coins (270-500)
 * Pure essence (10, 15 noted)
 * Coal (7 noted)

Herbs and seeds

 * Wildblood seed
 * Irit seed
 * Watermelon seed
 * Tarromin seed
 * Grimy tarromin
 * Grimy harralander
 * Grimy irit
 * Grimy marrentill
 * Grimy lantadyme

Charms and runes

 * Crimson charm
 * Gold charm
 * Blue charm (most common)
 * Earth rune (83, 114)
 * Death rune (5, 10)

Armour, weapons and projectiles

 * Adamant axe
 * Black warhammer
 * Mithril platebody
 * Mithril arrows (3)
 * Rune bolts (12)