Ultraman: Kidnapped From the Start and Made an Enemy of the Land of Light

The protagonist, Sai Lin, is Sai Luo's older brother. He's the beloved one with no romantic pairing. There are Tuo Tai, Ai Di, Jia Kai, Bei K, and other pairings, but no Sai Ze or Sai Bei pairings.

A mix of sweet and heartbreaking.

Will you choose the light, protect the weak, and keep the peace? Or will you choose darkness, destroy everything, and rule the universe? Whatever you choose, Sailesi will always protect you.

If the scales tip too far toward either light or darkness, Sailesi will appear. The light grows stronger and stronger. Weak people, you've been protected too well, to the point that your minds have turned foul and you've even started coveting the light that guards you. Then become nourishment for the darkness! The universe is being devoured by darkness? You last survivors pray for a miracle to appear again. Don't worry, come into the embrace of the light and have a good night's sleep. Leave the rest to me, Sailesi!

But Sailesi, oh, Sailesi, what about you? Isn't your name Sai Lin? Yes... you're both Sai Lin and Sailesi. You have to save yourself, too!