Loki

Loki Laufeyson (also known as Loki Odinson) is the adoptive brother of Hela, Thor, and Sigrid, and adopted son of Odin and Frigga and biological son and only child of Laufey.

In the wake of Hela's return, Loki was willing to abandon Asgard altogether and preferred to cause the Grandmaster to have an "accident" and rule Sakar with his older brother. However, Loki and Thor realized that Sigrid was on Asgard and feared that their little sister was a prisoner of Hela, or worse, but they didn't know she was on Sakaar, looking for her older brothers.

Sigrid
Loki does still love his younger sister, Sigrid, dearly,  as they were close immediately after she was born. He feared for her life when he thought Sigrid was on Asgard but she was sent to Sakaar to find her brothers.