User blog comment:PUNCHURPREGNANT/Gray and Silver Predictions/@comment-26399354-20140214120101

This might be wrong but today while I was reading the manga I kinda thought that Silver can be Ur's husband and Ultear's father. And Ur took Gray and Silver thought that he was risponsible for her death and since then he has killed Devils (Ice Devil Slayer Curse/Magic whatever the flip it is). It is a possibility.