Manga or manhwa about survival and transferring bodies

Question

I'm looking for a story that I've read a while ago and it's been driving me crazy that I couldn't find it. It's either a manhwa or manga.

Here are some of the details I remember:

• The story is set in (hell?) / hellish surrounding.
• I remember the main character as someone who capable of body possession or soul transferring ability.
• The main character can see the level or grade of a person body.
• the main character is weak (and forced?) to serve some stronger master.
• I remember there is a test tube containing a body of his master but it was stolen by a guy.
• There are instance where the main character had to fight the body thief where he at the brink of losing because his "body" reach his limits but not his soul.

Possible related theme: survival, demon like people, dark

Answer 1

This could be The Dungeon Master

In this Manga the MC starts as a bug whose job is to eat and defecate bricks, extremely weak and ready to die at anytime but as the manga progresses he and other beings just keep swapping bodies just keeping their souls intact.

They are forced to serve very strong masters for most of the story also. There are many people after his body in later stages because he gains access to a special one.

Like you mentioned this whole series is also set in a hellish dimension full of suffering for the lower beings.