Where do you get the upgradable artifacts?

[Zonc]

Game engine is random so every time you start a new game items are randomized. However, some items are at fixed locations (eg. Kerus' Sword at Road Architect)
Some upgradable stuff:
1) Archimage Staff
2) Royal Snake Ring
3) Steel Boots
4) Pain Skull (it does have two levels but it can be upgraded only by fighting battles)