The day Lyra and Titus laid eyes on each orher, was right after Titus and his band of rogues attacked and killed members of Lyra’s pack. With many wars and a ton of bloodshed over the years between the packs and rogues, things were bound to be bad for the two of them.
With Titus being a rogue Lycan and Brandi being a pack Lycan, their ways of life and experiences are completely different.