Greed.
The user has the ability to generate a large amount of ribbons from their upper back, although there is a limit to the number of ribbons that can be generated. Upon the usage of this ability, ribbons protrude from the user's back, acting as additional appendages. The length and width of the ribbons can be altered by the user, which could potentially turn the ribbons into thin, imperceptible threads. These ribbons are no different from normal ribbons until they're altered by the user.
Applications of this ability are that the ribbons generated could be used to set traps, swiftly restrain opponents, create flexible weapons such as whips, reel objects in, grab onto buildings and such as a means of transporation, and create complex structures such as giant fists for offense, or a cocoon or a dome for defense.
These ribbons can be styled and colored differently to produce different effects, only requiring the user to merely think about it in order to change their aesthetics. For example, a ribbon with a checkered design would have its strength amplified to great amounts, while a ribbon with a striped design would be extremely thick and durable. The ability to create structures such as a giant fist combined with the ability to strengthen it substantially would be a devastating offense against opponents. A cocoon made out of a large quantity of striped ribbons would be an excellent defence. Colours on the ribbons are for more of a cosmetic decision, although they can be utilized like the designs.
The user can also transform parts of their body into ribbons, using them to unravel their body in order to evade an attack, or to escape into a small, cramped area that their opponent wouldn't be able to access. If the user chooses to transform their whole body into ribbons, and then applied a striped design to themselves, they'd become incredibly tanky.
The limit for the amount of ribbons that can be generated by the user can be surpassed in exchange for a bit of the user's sanity or vitality (like Betelguese from Re:zero).
I think this ability relates to greed because of its versatility, which constitutes for the user's desire to do anything they can in pursuit of greed. Greed represents an excessive desire for more and will stop at nothing to obtain it, which is why the user is able to generate a potentially infinite amount of ribbons as long as they pay the price for it (not that it'd deter them, of course). This ability definitely sounded better and more creative in my head, but I think that it's still quite okay. I'll probably remake it depending on the feedback given, like Pride.