How to start the Dark Brotherhood without killing Grelod the Kind

Solution 1:

Let's talk about how this quest actually works internally:

• Grelod has to end up dead by some means.
• Grelod has 1 hit point, so any damage whatsoever will kill her.
• Children are immune to damage, but Constance is not. Attacking any of these people is a crime.

Here are some options I can think of:

• "Accidentally" summon an unbound ash guardian (from Dragonborn), allow it to kill Grelod, then kill it before it can kill Constance. This is challenging because Constance only has 30 hit points. I'm unsure whether you'll be held responsible for its actions, as the ash guardian spell is implemented differently from standard conjuration spells.
• Summon something else, then hit it until it turns hostile. It will probably also attack Grelod if she's in range. But it might attack others, and you'll be held responsible.
• Summon a flame atronach and kill it within range of Grelod. You'll be held responsible if the plume hits anyone other than Grelod.
• "Accidentally" hit Grelod with an area-of-effect spell such as Fireball.
• Cast a frenzy spell on Grelod, or reverse-pickpocket a frenzy poison with the relevant perk. Don't cast it on Constance, or it will be considered an assault.
• Tell yourself that you're just "roughing her up" by hitting her, and then pretend to be surprised when she dies of a punch to the face.

Solution 2:

Looking around on The Elder Scrolls wiki, specifically the trivia entries on Grelod's page, provides the following:

Under the influence of the Fear spell, Grelod may on occasion flee outside through either door of the orphanage. If Edda, the beggar sitting at the market, happens to witness this, she will come to kill Grelod. If necessary, she will even path-find through the orphanage into the walled-off yard to do the deed.

Here's a post by a user who successfully advanced the quest by essentially this idea, albeit in this case, Grelod ran off afraid because he got caught trying to steal her knickers. The Fear spell otherwise seems a reasonably non-evil option (though this depends on what you think of mind control and emotional manipulation via magic): you try to resolve the issue of her abuse at the Orphanage by getting her to leave, and by coincidence, a hobo murders her shortly afterwards. Not your fault.

Solution 3:

You could attack her with the Wabbajack.

I haven't tried myself, but according to this Reddit thread from Jame5G, if you transform her into a chicken, the quest thinks she's dead, despite the chicken being very much alive, and eventually transforming back into Grelod:

I used Wabbajack on the person of interest in the quest Innocence Lost. Hilarity ensued.

Turned Grelod the Kind into a chicken, which apparently kills her instantly and gives me quest credit despite from appearances her chicken form being unharmed. When the spell wore off she keeled over but not before unequipping her day clothes.

If anybody is going to try, better save the game before! It might take quite a few tries, as the Wabbajack attack has a random effect, and many of the options would actually kill the target. From UESP:

It can randomly cause fire, frost, or shock damage, absorb health, make the target invisible, heal the target, and in some cases instantly kill the target. Along with its offensive abilities it can also randomly transform a target into a chicken, rabbit, mudcrab, Dremora, or rarely into a sweet roll or a shower of 50 gold coins, along with a pile of ash. Transforming the target into a sweet roll or gold coins usually terminates the target.