I need information about Salamanders

So I am not a space marine player I'm a Tyranid player, I'm new to the hobby (I only have a codex and the rulebook) I do have SM2 and DT and love them both. In SM2 I coloured my space marine with space sharks (because sharks are my favorite animal). But then I liked the salamander colour pallet more and heard that the salamanders are the only sub faction who will choose to prioritize humans over their mission. And I really liked that and so I ask you, lifelong Warhammer 40k people to bestow upon me everything their is to know about Salamanders.