Broken Mirror Undead

The killer "Flying Stone" "retired" early due to an accident, and was reincarnated by a mysterious masked man into a world where magic and science coexist. There are magic sealers who fuse monsters with themselves, mad scientists who make monsters into living armor, and... The corpse of the eldest brother's fiancée? ... After exchanging his soul for abilities, "Flying Stone" felt more and more something was wrong. Wounds can be healed by lying on the ground, but will they turn to stone if you continue to lie down after the injury is healed? The strength is doubled and the intelligence is directly equal to one? The most outrageous thing is to summon a powerful thunder, but there is a half chance of hitting yourself?