Isekai manga where the MC is summoned as a support with infinite regeneration, is locked up in the castle and breaks out with vampire woman

Question

This manga features a MC much like the way Shield Hero does, for he is frowned upon as a weaker character without potential. However, a nurse from the castle where he's been summoned finds out after analysing the heroes that the MC has the ability to fully regenerate himself passively. From there, she locks him up for medical research, torturing him daily by tearing his limbs in order to test the limits of his regeneration and figure how that could be of use.

After enduring much suffering, the MC's drive to escape this nightmare triggers his affinity to ancient magic, teleporting him away from the torturing chamber towards a deeper location under the castle. There, trying to find a way out, he stumbles upon a lady sitting in a chair, having her blood constantly drained. They strike a deal, which consists in him offering his blood for her in order to escape. Figures she was a high level vampire being kept sealed for whatever reason.

They keep pressing forward studying the nature of the MC's abilities and end up befriending creatures which would be usually considered evil, such as ghosts and monsters, and eventually a Lich. Turns out the Lich was cursed to live as an undead due to his vengeful resolution to topple the tyranny behind the corrupt and cruel church, and kept roaming the land fixing whatever magical fuckups which concerned death he could solve. The thing is, I have no idea whatsoever about what this manga's name is, and haven't found a clue about it so far.

The vampire lady has long blond hair, the protagonist has black hair and the lich's face is a skull with a grey crown.

Answer 1

Is this My Companion Is the Strongest Undead in Another World...?

Yuuma, a timid college student who has been summoned to a different world. It was thought that a fun life in a different world would begin with the cheating ability given to you, but what was waiting for him was cold-hearted and cruel treatment. His body is chopped up, fear and severe pain run throughout his whole body, and it is a living hell that never ends. “Why did this happen to me…” Aside from Yuuma’s heartbreaking cry, the blessing of “immortality” continues to regenerate his body. Yuuma was made into an experimental animal of researchers who were fascinated by the possibility, but he meets a pretty girl by chance in the facility — after meeting Eva, his life in a different world begins to change greatly!

The protagonist is summoned to a kingdom with some schoolmates.

They determine that he's been blessed with the ability to revive, then lock up him up and start experimenting on him by chopping limbs off him and watching him regenerate.

After being held prisoner for some time, he's teleported out of his prison cell to a labyrinth, where he finds a female vampire who was also being experimented on.

They escape together, and a few chapters later they encounter a lich, who, after initially battling them, joins them as a member of their growing party of misfits.