I did it. No mods or cheats. So I had an island elemental and used dedeathify then turned into a mermaid. Only really if you want the sulani mana trait. Then she moved in with a werewolf. Lot traits on were both the leyline traits so chance of twins and vampire babies. Then tried for baby. Got twins — one in a vampire cot and strangely one in a black spellcaster cot. Aged up the twins and they are vampire/werewolf hybrids. They can drink blood, can’t stand sunlight, have thirst and vampire energy in their needs bar but they can only go up ranks in werewolf side. They can also howl etc and get raged. I’m not sure on everything they can do yet.