Two Realms: Fantasy Enlightenment, All Depends on Doomsday Zombies

[Double passage: fantasy + city + no harem + decisive killing] The protagonist suffers from cancer and is infected with a virus, which opens up the Rubik's Cube space. He can travel back and forth between fantasy and urban worlds. In fantasy practice, he relies on catching zombies in batches in the doomsday city. In the apocalyptic city, zombies are everywhere. Others are frightened when they see zombies. The protagonist is eager to try. The earth is in danger. It is not too much for the protagonist to use materials from the fantasy world to start a new era! In a fantasy world, the Rubik's Cube space transforms zombies into crystal nuclei. Others have worked hard for hundreds of years to break the bottleneck and seek immortality. It is better to melt an inch of the protagonist's crystal nucleus and automatically return lifespan and training points... The protagonist can use the returned training points to improve his cultivation by leaps and bounds, right? The protagonist uses the returned alchemy value, and the elixir-making rate is comparable to that of the Alchemy King! In order to make better use of zombies, it's not too much to prove immortality!