It doesn’t mattterif he transmigrated into the ML’s little disciple brother or master or opponent, but in the end he is still forcibly taken by the ML.
After transmigrating to many worlds:
MC: Come out system!!! The heck?! Why do these MLs not love their female goddesses, but insist on doing it with me! Aaaaahh!!!
System: …. __(:3」∠)_ Don’t ask me, I also don’t know.