From what Shane had learned so far, bloodlust was classified into different segments, with a simple bloodlust being the sole desire to kill someone and shed the opponent's blood, without the inclusion of someone's ideals and immense rage.
This was simply called a basic bloodlust, which everyone could create over time.
In order to create or improve one's bloodlust, the intertwined emotions, ideals, motives and desires have to become more apparent and also correspond with the creator of the bloodlust, his visualization, consistency and determination to follow his path.
As such, Shane couldn't just create any bloodlust and was either forced to create the most basic bloodlust in order to improve it slowly or comprehend an advanced bloodlust that was in sync with his ideals, desires and so on.
