He lived the same day for 100,000 years and trained all that time to become immortal.

[@ManhwaLink]

Name: I Get Stronger Just by Lying Down While My Apprentice Cultivates
Caps: 1-61
I hope you like

[@linux_steely]

Real name: The Time of Rebirth
Break Away from Endless Reincarnation
I Was Stuck On The Same Day For 100,000 Years
I Was Trapped on the Same Day for a Hundred Millennium
I was Stuck on the Same Day for One Hundred Thousand Years

[@Grant-m3z]

Under four hours gang

[@tonysparrow8602]

The dude doesn't have the charisma of someone who had lived that long 😢

[@linux_steely]

Real name: The Time of Rebirth
Break Away from Endless Reincarnation
I Was Stuck On The Same Day For 100,000 Years
I Was Trapped on the Same Day for a Hundred Millennium
I was Stuck on the Same Day for One Hundred Thousand Years