Greldo

Greldo is a goblin NPC that cannot be interacted with in any way except being examined. He looks to sport a steel spear and a wooden square shield, as well as wearing what looks like a bronze cap on his head. he also seems to wear a type of black goblin mail.

During the Black Knights' Fortress (quest), he is to obtain a certain type of Cabbage for the invincibility potion, but the player foils their plan by dropping a regular cabbage in the cauldron.

He is in the room with a witch and the Black Knight Captain, which is sealed off, despite having a door.

If you listen to the grill in the Black Knight's Fortress, Greldo says "Yeth, Mithreth" which could possibly mean that this goblin has a long tongue.

Interestingly, Greldo appears to be the only modern day goblin in RuneScape whose name does not consist of an unpleasant word and a body part, e.g. Wormbrain, Grubfoot, General Bentnoze and General Wartface.