Oldak is the greatest inventor of the Dorgeshuun, an advanced tribe of cave goblins. He spends most of his time in his lab at the bottom floor in his house in north-western Dorgesh-Kaan, just north of the bank.
Oldak is known for his excellent magical skills, a trait uncommon amongst the cave goblins. He seems to view magic somewhat like a scientist; his home is filled with strange metal instruments and littered with cables. Only after Dorgesh-Kaan's opening was he able to do much; the lack of available runes in the hidden city made things difficult.
Oldak will make players moving-over-distance spheres, if provided with un-noted molten glass and two law runes. He then proceeds to coat the molten glass in the crushed law runes, and when the glass is hardened, the orb has magical properties. When broken, the orbs will teleport players to one of several random areas in Dorgesh-Kaan.
Also, if a player inquires about the magic he has discovered, the cave goblin will explain some of his more recent discoveries, which will temporarily raise, or lower the player's Magic or Runecrafting skill by up to two levels.
Talk to Oldak. Ask, "What have you discovered?" You will get a different response depending on what skill is affected.
Runecrafting boost - Oldak lectures you on the construction of runes and you find yourself thinking about Runecrafting with greater clarity.
Magic boost - Oldak lectures you on the magic energies stored within runes and you find yourself thinking about Magic with greater clarity.
On the top floor of his house is a chest which can be opened with a lockpick if a player has a Thieving level of 52. The chest can be opened once every 3–5 minutes, and the loot obtainable from it is different from the loot of the other chests around the city.
Oldak was meant to sound like a cross between Carl Sagan and Doc Brown.
Out of the various instruments in his lab, there is a "Thingymajig" which resembles a stereotypical electric arc; an "Oojimafilp", which resembles a Van de Graaff generator which it also references with the examine text "Hair-raising"; as well as a "Magic ball" that bears a resemblance to a Plasma globe. All of them are common displays in science museums.
^Jagex. Mod John A's Twitter account. 16 December 2014. Mod John A: "Oldak the cave goblin was meant to sound like a cross between Carl Sagan and Doc Brown."