Earth-tier techniques corresponded to Grandmaster-level martial artists.
When Lu Yang had still been a Martial Grandmaster, absorbing the Azure and Purple Thunders had advanced his technique to the Earth Tier, Middle Stage. Compared with martial artists at the same level, he had enjoyed a considerable advantage in the total amount of true essence he possessed.
But after he advanced to Great Grandmaster, that advantage had basically been wiped out.
Great Grandmasters mostly cultivated Earth-tier techniques. Their total amount of true essence was about the same as Lu Yang's, and some Great Grandmasters even possessed far denser reserves than he did.
Last time, on the outskirts of Ice Soul Valley, Lu Yang had already felt his true essence running short.
Just one use of Yama Severing Soul had drained half the true essence in his body.
If he ran into an even stronger opponent and couldn't finish them in a single move, he would soon be trapped in the predicament of having too little true essence.
So, on the way back to Qing Province City, Lu Yang had already considered advancing his technique.
Only by raising his technique to the Heaven Tier could he gain an immense reserve of true essence and stop worrying about running short.
That was why, some time ago, when he bought the Tracking Secret Method from the Qianfeng Merchant Association, Lu Yang had also asked about the other three kinds of thunder.
Back when he was in Wanlin Prefecture, he had also asked at the Qianfeng Merchant Association, and the association had Water Thunder for sale at the time.
But Lu Yang hadn't had enough Spirit Stones then. He couldn't afford it, so he'd had to give up.
Now, he had acquired True Lord Lei Wu's legacy, and his wealth had increased by more than a