Baby's first Snarry Severus hid it for a very long time that he had a vampire inheritance. A part of why he hid that was because he knew that if he ever found his destined mate, everyone from both sides would try to kill his partner. He hated the very thought of losing such a prize. It was what he looked forward to when the end of the war was coming. To finally being free to find his mate. And then that whole jumble of a 6th and 7th year for the Potter boy and his year group happened. Severus soon found himself dying from a massive, poisoned snake bite and desperately hoped he made it through for his mate in the end. He wasn't sure when Harry and his group showed up but- Harry? Wait- No! Not him! Oh, they'd never be compatible! They hate each other's guts! But Harry just smiled at Severus and done as his mate asked, ending the war and finishing off what remained of the Death Eaters. But of course Harry wouldn't let his mate die.