Title.

I sneaked through his base, completely undetected. I then pickpocketed him and knocked him out before leaving, and what I think that achieves (from a kind of RP perspective) is letting him know who is the greater assassin. One moment, he's doing his daily business. The next minute he wakes up to find his possessions gone. I'd like to think this makes him realize he isn't so great after all.

On my more chaotic playthrough, I simply killed him. Corvo was hungry for revenge. And he got it.

First time I didn't do anything with him, I just sneaked thru the place. Didn't make him unconscious, instead he will just notice that his key is missing and wonder how the hell that happened as he been in his room the whole time

Beating him up and then sparing him is a better option

I was doing the Shadow achievement so

It's just my first game, met him last night. We were fighting and during the fight I blinked away and noticed he was searching for me so I snuck up behind him and choked him out. Then I put him to bed, snoring away. When he wakes up, he'll know who he's second to.

First time I came up behind him and killed him instantly the second time I had a entertaining dual with him. Which lead to his death.

The very first time, I picked the key off his belt (but didn't subdue him) and Blinked out with nobody the wiser. Ghosted that level.

Since then, I've handled him all possible ways. For some reason, I like to beat him in a fight and then let him live.

Non-lethal. Stole his key, his belt pouch, and left the premises.

Tried to approach with time frozen and simply assassinate him. Much to my surprise, he can also move when times frozen, as well as being able to freeze it himself. So I got into a duel with him and the assassins he calls in. I'd alternate between swordfighting Daud and lining up shots on the assassins with the pistol while time was frozen. Eventually, he teleported to the other building where the duel continued for a short while. I spared him after he gave his speech.

Might be the best moment in the game, although there's a lot to choose from.

There's no discussion, crawling through the shadows, swiftly stealing his pouch and the key under his nose and leaving - That is THE only way!
He will not only feel humiliated more than he would if he lost in an honest fight, also he would know that if Corvo could do just that, he could drive a blade right through him as easy as breathing!

I snuck through his base, silently and without being seen. I choked out every single assassin under his command... even his dogs, and put them all somewhere safe and sound. They'll really wonder what the hell happened when they wake up. Especially the four I stacked in Daud's bed.

As for Daud himself, I left him untouched. He never knew I was there, even though I stole the key from his desk, and the charm from his belt. He'll know how it happened, and he'll realize that I could have killed him at any moment.

I killed him dead. But that was on my high chaos play through. This time I will simply steal his key. I kinda want to fight him and then spare him but I fear that, seeing as he summons other assassins to help him out in battle it will result in high chaos.

I battled Daud and his assassins on low chaos. I killed a few other assassins and weepers throughout the level and Granny Rags as well. The game gives you a bit of leeway there.

I killed him because he was being stupid. When he was mumbling to himself in his base he says he would take back all the money for killing the Empress and says that "nobody should have to kill an Empress". The thing is that he didn't HAVE to kill her. He chose it for the money, and there's no evidence that he was forced to do it by the Lord Regent.

Just because there's no evidence, does that mean it wasn't so? Hiram Burrows (or the Lord Regent as you call him) is incredibly corrupt and I think he could've forced Daud into it or he may of revealed Daud to some authority and had him executed.

EDIT: In fact, Daud is an intelligent man. To me, it seems like his line, 'nobody should have to kill an Empress' makes me think that Hiram did actually force him.

well the first instance sneaked up behind him and assassinated him, then remembered clean hands lol so reloaded and just choked him. For that got the mercy achievement for sparing him though

Best game was the first. I got detected, so a fight started. I hit Stop Time, Daud said "nice try Corvo" and we proceeded to duel in slow motion. At one point he blinked away and I found him nearby, badly wounded, and talked to him. I ended up sparing him.

It was awesome, best boss fight I've ever had because it used artistry and characterization for drama instead of just a long, boring struggle with a character that has endless hit points.

In my 2nd game I couldn't reproduce this- he kept dying in the fight, so I ended up choking him out. I hope he goes back to Serkonos and buys a vineyard on some hill and finds some peace. He was just the knife that the real power wielders used to kill Jessamine. If it hadn't been him, they'd have found another way.

Oh, I showed him who was boss. I left every last one of his guards unconscious and snuck up and pick pocketed his stuff and knocked him out. Then I dumped his snoring ass between 3 sleeping guard dogs. Let him know he was my [censored].

I crept up on him and choked him out then put him on a pile of dead assassins at the top of the dilapidated building outside.

I froze time and he said something along the lines of: "nice try, Corvo". After that, a mighty duel ensued and I just ended up killing him. Didn't even know of an option to spare him.

I walked up to him, and "dueled" him (stupid flunkies), beat him, and let him go.

The optional conversation with Daud happened on my first try by accident, but afterward I had trouble getting it again- he would die in the duel a lot. I reloaded a few times and found that when he's injured, he blinks away to heal and then comes back. Only after doing that one or two times, he doesn't come back, then he's waiting for you out on the platform outside the room where you first find him. It's quite a visual juxtaposition because where he's slumped for that conversation, you have line of sight right to the statue of the empress.

Beat him in a duel my shooting him repeatedly, but let him live; the infection probably killed him in the end. Either way, he was just a tool. The Lord Regent received no such mercy, I fed him to rats.

Strange, both times I fought him he went down instead of dying. Maybe only use your sword on him? I've heard other people say that the pistol/crossbow will kill him.

No, I actually switched to using crossbow and only using the sword to block in order to get the confrontation scene.