Late Stage Capitalism

I have. He didn’t.

He did find Erkenbrand and lead him and his men to Helm’s deep, but his presence alone drives the hillmen to collapse in fear; he never lays a hand on them. Erkenbrand and his troops rout the orcs and hillmen, and kill quite a few (mostly orcs, as the books note that at that point thanks to Gandalf many of the hillmen lost the will to fight and surrendered, and the Rohirrim accepted that surrender).

So I guess if you want to stretch the definition of ‘kill’ to ‘told an army their king needed help and showed them where to go’ then I suppose you could lay those deaths at Gandalf’s feet? Although I would argue he actually saved lives there, since if they had continued fighting Erkenbrand’s men and Theoden’s men would have torn all the hillmen apart.

At the battle of Minas Tirith he holds the broken gate the whole night against the leader of the Nazgûl (by parking himself in front of it and refusing to move), but then once backup arrives he has to turn and run for it to save Faramir from being burned alive, so he doesn’t get into a fight then either.

At the Battle at the Gate him killing, specifically, isn’t mentioned either way. One could assume from the writing that he at last drew his sword and finally killed people in support of being as big a distraction as possible, but Tolkien never explicitly said, like he did for some of the other characters. All he says is:

Upon the hill-top stood Gandalf, and he was white and cold and no shadow fell on him. The onslaught of Mordor broke like a wave on the beleaguered hill

Which could just be him intimidating people again, although I doubt it. But even then, given how humans in the employ of the Dark Powers fear him so much, it’s more likely he was just fighting orcs.