Although not mentioned, Corbonek is sealed and its manifestation destroyed for the rest of the war on the use of the Beast, and in turn the benefits of No Sane King are lost. 

I don't have to mention its intelligence to you, or how it will look. You'll find out when it's used. 

It's controlability is a given, considering Pellinore's riding rank.

It's stronger than you. Figure it out.