Looking for a manga i forgot the name of

[Neko_Chan]

It was about demon lords i think? And they only had like 200 years or something to like so they had to replace themselves, and they summoned new minions with token things that they could combine which would increase the chance of something good being summoned. I think the mc wanted to build his dungeon above ground and between a major city and another dungeon.

 

[TreeMan123]

https://mangadex.org/title/23853/maou-sama-no-machizukuri-saikyou-no-dungeon-wa-kindai-toshi

 

[Neko_Chan]

@TreeMan123 thx m8