It was a hassle to name rings, so calling them [ring1], [ring2], [ring3] wasn't too bad. Ainz even saw people naming [thumb ring], [index finger ring] and [middle finger ring].
Ainz's friend Takemikazuchi used two Tachi if the situation warranted it. He named the 8th generation of one of the Taichi as 'Takemikazuchi Mk 8'.
It was the same for naming this red cape.
Because he copied the dark hero of an american comic, it was named [Spawn Cape].