Duan Ling Tian had changed; he was no longer the person he used to be. One of the things that changed was his view on the people of the mundane realms.
For as long as he lived, as long as he had sufficient strength, he would never allow those who tried to harm him to live. Even if he was not strong enough to kill them, he would return after he had gotten stronger to kill them. There were also instances when he spared them because he judged it would be more beneficial to let the other party live.
An example was the Zhong clan in the Profound Energy Land's Skywind City. At that time, the king-rank Zhong clan had sent death warriors to kill him. When they realized they could not kill him, they had tried to make amends by sending him all kinds of treasures.