FAQ Breakdown - Frequently Asked Questions by the beginners

[Rookeye]

The big 4 concept (hydra+, cirus+, avenger+, living flame+) is outdated. Focus on beating the EB 15 times. You should be able to do it with friends by the time you're around level 30 now. Just search and add friends from leader boards. Friend request a whole bunch and a few will accept.

It may be outdated, but my few maxed Big 4 helped me get my first few EBs. *shrug*

To answer the original question: to unlock armor, you need to level it up as follows:

1/30 armor = level up to Lvl 15 (halfway)
1/50 armor = Lvl 25
1/70 armor = Lvl 35

That is to say, if I have an armor that maxes at Lvl 50, I need to raise it to Lvl 25 in order to unlock that particular armor in the future. NOTE: To actually make the +, you need to create a new one! after you've unlocked the first. The + will be the second one you make.