Construction
From IdleOn MMO Wiki
Construction is a W3 skill that Squire specializes in.
Build 27 unique Buildings!
There are 9 "utility" buildings that help general gameplay (3d printer, talent book library, etc).
There are also 9 "Wizard Defenders", used for Worship.
The last 9 are "Shrines", which you custom place on any map in the game, and it boosts a certain stat -- you can also LEVEL UP shrines by afk-ing on their map! But if you move the shrine, you'll remove all its EXP to next level (so you don't constantly move them around)