Gothmog vs. Sauron

[Andsigil]

Originally Posted by Eönwë

We constantly hear of Sauron being second in command to Morgoth, yet it is Gothmog who leads the armies. It takes a great elven warrior to kill Gothmog, whereas Sauron could have been killed by a dog (however great he was).

I wouldn't always associate prowess with rank.

Second in Commands, to put it in anachronistic terms, often function as Executive Officers or Staff Chiefs, while the actual units are commanded by people subordinate to both the commander and his second. It has been this way for a long time, across many cultures.