I like this character from my Steven Universe Star Trek AU, but it's kinda confusing to explain.
The short version is this: Blue Diamond senses a dying Vulcan kid, and he reminds her of Pink. So she makes a snap decision to save his life, by getting his katra and then shapeshifting into him. So from then on, most of her time is spent just letting the Vulcan live in her holographic body, like a virtual machine running on a laptop.
But sometimes, the Vulcan - his name is Soral - will want Blue Diamond to reassert herself for one reason or another. This essentially merges them temporarily into one, female-identifying person. (This person doesn't have her own name, but she usually goes by Blue Diamond unless that would be confusing.)
It was almost certainly Rose who gave her the novelty t-shirt from the local deli.
