From the beginning, Karsha planned to complete the quest and start training for his biggest challenge -killing the 10 Overlords. During the way, he had luckily chanced upon some items and techniques that further elevated his strength to the next height.
One of the greatest gifts he had got was the subspace where he could train 24 hours there but just spend an hour in the real world. It was a great gift that couldn't have come at the most opportune moment.
So now that he is done with the quest and has awakened the 8 elements, his next plan is to start the training. 864 days sounds like a long time but in the world of cultivation, that could be considered a blink of an eye.
He first wanted to train his movement technique to the second level before tackling the other techniques and skills. With the first level mastered to the S rating, Karsha can now move to the next level, the Thunderstep level.