Stallia and Delilah are sisters, but not many realize because of their different personalities. Stallia is a shy, sweet, kind and thoughtful, but is an idiot, (although more competent and capable than Cubot) and has low self-esteem because of insults from others for her and her sister being different. (Although if you make Stallia mad, you'd have to be Hyper Sonic AND have the Super Peel-Out to escape) Delilah is very quiet, (but when she says something it's direct to the point) straightforward, brutally honest, confident, ambitious, sarcastic, has a hidden heart of gold, and is very smart (smart as or possibly smarter than Orbot)
Also, Stallia has a huge crush on Orbot, which Cubot told him after Stallia told Cubot. (although Orbot did have to wear him down) Cubot also has a crush on Delilah, something Orbot had to point out to Delilah
The two sisters from another planet have traveled across planets far and wide in search of a job before finally getting one at Modern Eggman's place (Most of the Sonic Universes in my Sonic Multiverse are like if Classics and Moderns lived in the same dimensions) and got to know the other robots. (Normalverse's Scratch, Grounder, Coconuts, Modern and Classic Metal Sonic, Orbot and Cubot) The sisters work well in battle and have battled all of The Freedom Fighters (comprising of many Classic & Modern Sonic characters) multiple times before.