Slayer tasks from Krystilia now will give you an opportunity to get Larran's Key OSRS by killing monsters in the wilderness. With the keys, you can unlock the Larran’s chests, which have the same items as the Brimstone chest except unique items.

A perfect chance to join RS3gold coupon promotion on summer time: up to $10 cash coupons for RuneScape gold, OSRS gold, and all other products are available for you from Jun. 27 to July. 4.

Open Larran’s chest with Larran’s key

After this week’s updates, there is a chance for all of you to obtain Larrans Key when killing monsters on a slayer task assigned by Krystilia. Then these keys can be used to open Larran's chests, which can be found in the Wilderness.
It is the same as Brimstone keys, the chance of getting a key depends on the level of the monster that's dropping it, so higher-level monsters have more chance to drop it. You must know that these keys are untradeable, but they can be dropped to a PKer on death if they are not protected items. Another point to note is Ironman PKer cannot get someone else's key in this way, so key is destroyed completely.

Remember the specific locations for Larran’s chest

The small chest can be found at north east of the Chaos Temple in level 18 Wilderness. Because of the location easy to get, so this chest will drop slightly worse off in numbers than the Brimstone chest.
The big chest can be found at the west of the Pirates hideout of middle floor in level 55 Wilderness. These chests will be dropped more than the Brimstone chest for the more dangerous location and lack of access.

Furthermore, you can buy cheap Rs3gold or runescape 2007 gold with 6% Off(code"NEW6RS") from https://www.rs3gold.com/ at anytime.