If They Mated...
Let's suppose that Valgarv did find love in the arms of one of the Slayers females. Here's what their children might look like:
Valgarv & Lina
= 
Valgarv & Sylphiel
+ 
= 
Valgarv & Amelia
+ 
= 
Valgarv & Filia
+ 
= 
Congratulations! It's a Jessica de Alkirk.