Luma is definitely heartened by the information that there's no control mechanism in place. In fact, she looks almost cheerful - the happiest you've seen her since this whole mess started.
The mood is ruined, however, at the mention of Harfang. The name itself, spoken, resonates with power*, and there is an immediate sense of presence - Harfang is very clearly paying attention, right now, to you in particular. On the plus side, there seems to be no hostility in his presence; if anything, there's a hint of... approval, maybe? Something like that.
Luma's reaction is almost as fast - her fur bristles, her tail puffing up to twice its normal size, her ears go flat, and her sword appears in her hands. As there is nothing actually physically there to fight, though, she's left glaring and hissing at empty air.
* The power of a deity's actual name is proportional to the power of the deity in question. Harfang, as gods go, isn't actually all that strong - but the power is also inversely proportional to the number of people who know that name. And you could count on your fingers the number of mortals who know the name "Harfang".