(At this point, i should make an account >.>)

So, i got a question

"
Q: What do the + sign in my summon/weapon means?
A: The + sign means that when you use that summon/weapon as upgrading fodder, it will pass over +1 to the character/weapon being upgraded.
Each + increases your character/weapon HP by 1 and attack by 3.
it is not recommended to upgrade KH with + as the effect is insignificant. Use + to upgrade summon and weapon instead.
The maximum + is 99.
"

my question is: Is the only way to get +weapons/+eidolon/+Kamihime is via gacha? OR there is a way to make a "+0" into a +1?