I feel like we need another set that goes from 2* to 5* like the others that are in the title.
For example, a cyborg set which has an alchemy tree like this:

--------- Earth Cyborg-------- Gaia Cyborg
---------- Green Cyborg-------- Element Cyborg----- Element Toy
Cyborg---------- Cyborg MKII---- Cyborg MKIII--------------- Cyborg MK Final
---------- Mecha--------- Toy soldier-------------------- Gremlin Soldier
--------- Broken Toy---------------------Malfunction Toy

For Shield, but shield at the end of the name, and same for helm and armor
Green series- Elemntal/Normal defense
Elemental is weaker that Earth but has fire resistance e.t.c
Cyborg MK series has normal defense and health boost (Maybe some damg. bonus)
Mecha is a normal/ piercing defense and broken is slightly weaker but has a speed bonus.