Not a Demon Lord
Pretty good novel, I haven't seen this sort of novel before, wuxia+dungeon defense. Anyways MC died 3k years ago, and now partially revived, but needs to kill intruders to regain strength. To lure intruders into his tomb he has a system that's pretty much does the dungeon defense bit. His disciples from 3k years ago are bigshots who want his legacy. Review from C15.
Couldn't help but compare this book to the "I became the gravekeeper for the great pyramid of Giza" book due to the tower defence theme. This book is literally the same but with a cultivation background and with a slightly more established motive. Since I gave 9.6/10 for the Gravekeeper book I'll give 10/10 because I prefer this one.
Basically guy reincarnated/Isekaid to a xianxia world become number 1 expert and about to die. So he got a system before his death and the system promised that he will be revived as long as his Disciples reach Saint realm, which they did 3000 years later. He got partially revived because before his death he got an enlightenment and makes him more powerful, therefore more energy was needed to revive him, which the system does not have. Now he is forced to basically becomes a dungeon core and have to kill people to revive. Imo it's not bad. There's some inconsistencies with some term but not a lot. As for other things such as character.. Well it's only 20 chapters and until now there's really not much that the Mc has done.. Overall I would say to give it a try, might be good might be bad.