Before he even knocked, Hel knew Hermod was in her realm. Poor queen she would be if she hadn't made all the necessary preparations for detecting unwelcome visitors. It took courage to enter her realm, but even so, it was as difficult as it was to navigate for a reason. She would need to speak with Modgud about letting just anyone pass her bridge.
It also didn't take a genius to figure out he was here because of the man seated beside her. Baldr's death had likely rocked Asgard right to its foundations. Immediately upon his entrance to her realm, Hel had sought to impress the favored son of Odin, giving him the seat of honor at her side. She wished to show him every kindness and respect. Who knew? For would it not be fitting should the shining god of Asgard become the lover of one of Loki's monster children?
That was for later. Right now she had do deal with the unwelcome attention Baldr's death had attracted to her realm. Nodding once, Hel gave the questioning attendant permission to open the doors. She reached over and placed a hand on Baldr's arm, both in significance of her now ownership of him, and to suggest to him that he not cross her. She turned to give him a warning look, softening it immediately with a smile.
She might want to impress Baldr, but Hel was still going to make it clear that this was her realm. Odin put her here, not by her choice, and she would be damned if anyone would try to usurp that. Here, they bowed to her.
Asgard be damned. She built this world from next to nothing, and was proud of her accomplishment. And here, even Odin could have no say in what went on. Which was who she was sure was behind Hermod's sudden arrival so quickly on the heels of Baldr's. She sat up straight on her throne, her hand still on Baldr's arm, her chin held high as she waited for the messenger to enter her presence.