Defiler

+1 to Hit for all shots fired at it, due to being so alrge.
Extra attack dice and +1 WS for additional attackers in close combat do not apply against a Defiler. May never be pinned unless engaged by an equally large opponent (other titan). 
May move in all directions without turning. May turn like a regular Walker if it wishes. Will gain +1 attack for each additional close combat weapon added.

See rulebook page 66- too long to describe