Okay this is interesting. Once you get Shadowmere, you have a constant companion. Period. Fast travel anywhere, Shadowmere is there whether you want him/her there or not. And, after doing an assassination Shadowmere will attack the guards if the assassination is in the same area like the one in Ivarstaad. YOU will not accrue bounty in the region. You will notice your total bounty going up, but it will not say WHERE your bounty went up, like it does when you attack a guard. You can walk right up in the fray, the guards will not attack you. You can hop on Shadowmere, and ride off. They will fire arrows at Shadowmere, and the guards will show up as your enemies, but you're not the target.

This is weird. I guess you're joined at the hip, but different.

Anyone else notice this? or is this a bug? or is this the way horses behave? or am I just noticing this because Shadowmere actually survives these encounters.

I can only say this about normal horses as I haven't done any DB/TG stuff:

1) My horse always Fast Travels with me.
2) My horse always attacks ground enemies that I'm attacking or that attack me (he/she will run from flying dragons and sometimes archers on walls).
3) From what I've read about Shadowmere: normal horses are not nearly as hardy as Shadowmere and do not respawn (I don't think - I've never waited the amount of time it takes Shadoemere to respawn.)

Damn. Nice.

If they don't see you, they shouldn't turn hostile, therefore Shadowmere should have no reason to attack. His never attacked anything that wasn't hostile in my game.

Yea, Shadowmere only charges at hostile NPCs for me as well. If I want to sneak into a Fort, I have to "park" him far away. LOL I love Shadow though! He's a cool horse!

Ah, I think they got a glimpse. The target was standing out in the middle of the road. 100 sneak + muffle + muffle boots + watching the guards. The guards may have started to turn when I did the hit, and Shadowmere attacked because they were going hostile, thus taking the heat off. Now if I could only get him to eat an apple.

Shadowmere respawns? Where?

*edit: apparently where he dies, so now if only i could remem....oh snap, outside the college where all those things showed up

Shadowmere should respawn where you first got her, i.e. that black sludge pool infront of the Falkreath Sanctuary.

Yea I put him far away from where I going then walk.

So far 3 people refer to Shadowmere as male and 1 person refers to Shadowmere as female...

So which is it?

All of us who've referred to this one as male are wrong. Shadowmere is female according to the TES Wiki. Also it works better considering how brave and protective she is.

I alway think her as a female even in Oblivion but really I don't know.

EDIT
I did say him in my first post I think because everone else was.

Shadowmere was female in Oblivion. Astrid refers to Shadowmere as he in Skyrim. So we could argue all day about what six it is.

Love/hate relationship with that horse. If you're overburdened like I am a lot of the time with loot or crafting items for skills, she's a life saver. But I HATE how she charges into a battle, oh how I hate it. A dual wielding forsworn can still wipe her out in a couple double strikes, and an ancient dragon can kill her in a bite. Even more aggravating when you dismount overloaded only to find out there's an archer sniping at you and she takes off after it leaving you to crawl all the way there.