[Loslote]

Eowyn - it could be argued that she herself was the deadly one, whereas the mighty warriors' deadliness came from their skills and weapons, not an innate quality within themselves. Eowyn, however, was in a way fated to kill the Witch-King - no one else had the power to do so. To the Witch-King, Eowyn was the only deadly one.

Gaffer Gamgee - I'm having a hard time seeing him as deadly, I must admit.

Glaurung - not just deadly, but with a added evil spice to it. Deadly plus, if you will.

Gandalf the White - Gandalf was deadly more in a theoretical way than in a bash-in-heads way, I think. Sure, he killed some guys, but more importantly, he was deadly to Sauron's plans.

Forweg - deadly? Maybe 'slimy' or 'nasty' - he doesn't seem like the kind of guy I'd like to hang around, but also not so very fearsome in battle.

Mount Doom - dangerous, perhaps, but not deadly.

Ancalagon - supposedly the most powerful dragon ever, but we don't see it. Moreover, when talking about him, we get quotes like "nor was there ever any dragon, not even Ancalagon the Black, who could have harmed the One Ring" - so, basically, this dragon, too, is dangerous but was never proven to be deadly.

Sting - going by the Eowyn logic, Sting, too, possessed a certain amount of innate deadliness that, for me, sets it apart from the warriors in this list. Sting, however, does require a wielder in order to be deadly, which somewhat negates its innate deadliness.

Carcharoth - dangerous, for sure, and deadly to all sorts of little elf-soldiers - but not so deadly the time we see the most of him, so I'm not all that inclined to think him especially deadly.

Gothmog - I would say Gothmog is deadly in all senses of the word. Killing things left and right, that one, and not just the sort of evil dude to kill little elf-soldiers by the dozens only to flop when he gets to a main character - no, Gothmog doesn't care if his foe is himself deadly, he just goes right ahead with the killing.

Gothmog, for me, is definitely tops, followed by Eowyn and Gandalf.