Marceline's heart skipped a beat when Kira called her Stella. He was also asking her to mark him as he was done marking her. Through this mark, Kira would be able to protect Marceline from other vampires who would try to hurt her.
He would know if Marceline would be in danger. He would feel her pain. And at the same time, vampires would know that she was his. And whoever tried to hurt her, they would know that they were challenging Kira.
Now, it was Marceline's turn to strengthen their bond further. Once she marked him, there was no turning back anymore. She was bound to him forever.
'Should I do this? But I'm not certain about his real feelings for me… What if this is part of his revenge?' Marceline contemplated for a moment.
But Stella, her wolf, could no longer wait. She wanted to mark her mate, Kira. 'Let's do this, Marceline. Claim Kira! Our mate!'