Queen Regent Cersei Lannister

When Queen Regent Cersei Lannister enters
the battlefield, search your library for a Lannister
card, shuffle your library, then put the chosen
card on top.
Whenever a Lannister creature you control dies,
put a revenge counter on Queen Regent Cersei Lannister.
{b}{t}, Remove a revenge counter from Queen
Regent Cersei Lannister: Destroy target
legendary creature. Activate this ability only if
you are the monarch.