As of now, there is a new item called Kal Fragment.
What is it for
Kal Fragments are used to exchange for Kal Runestones. 300 Kal Fragments can be exchanged for 1 Kal Runestone at the Kals Exchanger in Argent.
How to get it
The Kal Fragments are gotten from the pets. Every time the pet grows it gives a Fairy Coin, and from now on, it will give a Kal Fragment too. The Kal Fragments will be added to the Temporary Bag, so make sure you have at least one empty slot there otherwise the Kal Fragment will drop on the ground.
Tips
Low level pets have faster growth rate, grow faster. As the level of the pet increases the growth rate is decreasing. Therefore, a low level pet, a level 0 pet, will give more Fairy Coins and Kal Fragments than a high level pet, in the same amount of time. So, equip a level 0 pet, and have auto rations in the 3rd inventory slot, when you go AFK or just simply are not in need of your battle pet, high level pet.
Fruit of Growth doubles the pet's growth rate for a duration of 15 minutes upon usage, meaning you will get Fairy Coins and Kal Fragments even faster.