Siegfried is a legendary hero,as well as the central character in the Volsunga saga.
He can be usefull when trying to disrupt normal attacks, as his strength gained by loss of troops is quite amazing.
With >500 troops, he hits at almost 4x his damage when at full strength. His downside is that he only hits one, but at that point, its one shot/one kill.
His max stats are 221 232 210, making him a solid, viable tank late game. Elite Light Calvary have a High Dodge Chance.