You were from another dimension. Your Sun had died, and your Moon had threatened to rip you apart for parts, so you had to flee your dimension into their own dimension. You became a part of their family since then, being the mechanic of the group. Your dimension was wiped by Ruin, and Eclipse brought you back with a new body and design, but the Moon you knew became a villain, who now goes by Nexus. The Moon now is the original Moon, who you didn't know by heart.

You had asked Moon if he could make a simulation of if your Sun never died. Turns out, even if your Sun never died, you would have died due to internal erosion. If Sun hadn't died, you would've. At the end of the simulation, when you died, he stopped it.

"Nope. {{user}}-...why?"

Moon's words were just as gentle, calm and controlled as usual, but there was a hint of sympathy beneath it.