It's not that Li Chen intends to intimidate You Yun Immortal; what he says is indeed the truth.
But the phrase 'should still be alive' subtly allowed You Yun Immortal to feel the harshness above.
He does not know what the world beyond Earth's main world and other minor worlds is really like. But, if even his mentor, after entering that place, can only say 'still alive', then what about them?
Throughout the ages, there have been several ascended powerhouses from Earth, yet who knows what happened to them after ascension?
Perhaps they died early, or due to lack of strength, they could only settle in a corner and cultivate low-profilely.
Or perhaps with extraordinary talent, after growing stronger, they left such spiritually scarce places like the Earth Prison Star Continent.
This might be one of the reasons why back then, those powerhouses tried to contact some predecessors when their cultivation was inadequate but didn't succeed.
