Dabi definitely still doesn't trust César at the moment but he'll still walk beside the man. He wants to hope that Mag really is doing so well, that she's happy and loved like she deserved to be back home. Out of everyone in their rag tag group, Magne 'deserved' the treatment they all got least of all in his opinion. He wants so badly for her to have a better life here in this weird place.

The most César gets from him now is a grunt. Where he had been talkative before he's now way more focused on finding his friend. He needed to see her alive and whole. He needed to replace that gruesome image in his head of what had been left of her after Overhaul had...after he had killed her.